A Comprehensive Study of EverQuest's Classic Resist System

[Torven]

Over the last year I've been spending a lot of time trying to figure out as much of EverQuest's original resist system as I could and this document will detail my knowledge of it. This research is largely based on decompiles given to me by Kicnlag and some I've produced myself. Kicnlag discovered that the Kunark and earlier era clients had the server-side resist logic in them. (Sony stopped including it in the Velious and later clients) This is a huge discovery and it turns out that the classic resist system was considerably harsher than we realized. As it plays a very important part in the balance of the classes and the game's difficulty, it's important to get it accurate.

We used a program called Ghidra to spit out decompiles of the client binaries and we then figured out what most of the variable names and literals are to make the code understandable. Since I'm familiar with the modern resist math it wasn't that difficult for me to decipher what the variable names are. We have only two clients from the pre-Kunark era, which are February 16 1999 (the launch CD client) and March 21 2000 (one month before Kunark). There are many clients available in the Kunark era however and we are able to view some of the evolution of the algorithm up to Velious. The latest client with the resist logic is November 29 2000 (one week before Velious) and that is the most valuable binary for this research.

All but the February 1999 client binaries were obtained from here: https://web.archive.org/web/*/everqu...wnload/patch/*

Decompiles are extremely compelling but not necessarily 100% proof. I checked all available sources to try and verify the code authenticity, and I can say that everything found in the decompiles ended up correct and explainable. Not all of the resist logic is found in that one resist function however, and the Kunark clients do not have some of this remainder. For that I had to figure it out the old fashioned way. The only significant pieces I could not nail down were wizard and dragon breath lure behavior from December 5 2000 until Sept 4 2002 but otherwise this document should explain just about everything. Although there could be unknown unknowns.

Note: in this document I'll be referring to the entire time period from before September 4 2002 as "classic" unless I say "pre-K classic" to indicate the era before April 24 2000.


Classic Resist Rolls

The most significant finding we discovered is that in classic EQ, spell resist rolls were 0 to 99. This was the case up until September 4 2002 when it switched to 0-199. A "roll" here means a randomly generated number from X to Y, which is then compared against the effective resist value, which is the target's resist after all modifiers are applied to it. If the roll is lower than or equal to the effective resist value then the spell is resisted.

It's important to understand the significance of this. This means that every single point of resist from gear or buffs increased your chance to resist an all-or-nothing spell back then by 1%. Resists were essentially twice as powerful in the classic eras when resisting against most spells. (there are exceptions which I explain later) This meant that the buff Group Resist Magic by itself increased your chance to resist by 55%, so only having this buff on while naked for most races/classes made the magic resist rate 80%. Resisting all-or-nothing spells in classic EQ was much easier, for both PCs and NPCs.

This finding explains why some of Sony/Daybreak's developer comments mentioned a "resist chance" variable in place of what is obviously "effective resist value", which in the newer logic is one resist value = 0.5% resist chance. Prathun's 2010 pseudocode says this and some other sources also confused resist chance with resist value which I mention in my Charm, Root, Lull thread. The reason is simply because in September 2002 Sony changed the scale from 0-99 to 0-199.

This also explains why many resist modifiers seemed so weak/trivial. The resist modifier from level difference for example is found in the old clients, which is level^2 / 2. So an NPC five levels above you only reduces your effective resist by twelve points, which seemed rather trivial under the PoP era mechanics. This caps at -40 in the case of a higher level PC vs an NPC, meaning when fighting green cons you only gain a 40 resist value advantage. If the scale is 100 points wide instead of 200, then these modifiers are twice as significant.

The September 4 2002 patch was a massive buff to caster DPS for this and other reasons which I will go into. This is the primary reason why casters are so overpowered right now on the emu servers in the early game.

Other Evidence For The 0-99 Scale

I did check for logs to try and verify if the 0-99 scale applied in Velious and Luclin eras, and it was easy to find. In November 2001, three weeks before Luclin opened, I had produced logs against the mist panther NPC in Wakening Lands to parse my DPS with various weapons. One weapon was my Scepter of Destruction. This weapon procs Anarchy. Before September 4 2002 it was an all-or-nothing spell. The mist panther has a typical resist value of 35 MR and it's a level 60 mob so the level difference modifier does not apply in this case. I added up the resists in my mist panther logs and the resist rate was 36% in 300+ procs, which was the expected rate.

My personal logs yielded more evidence: I found in them that I was resisting certain spells very easily without a bard, like Thunder Blast. That spell is cast by blue drakes in Temple of Veeshan. I was a warrior with Halls of Testing armor, and I resisted 60 out of 61 casts, which agrees with a 0-99 scale, as with that equipment the MR would have been under 200. I have screenshots from the time period showing my MR value. (note: the spell was all-or-nothing at the time)

I also found a log from the tipa16384 archive (https://github.com/tipa16384/harcour.../tree/main/DSR) which agreed with 0-99. The Nina character was a 48 halfling warrior with a cold resist buff on (so 65 CR) while in the Great Divide cave fighting a AoEing wurm, and the full hit rate was only 9 out of 36 casts (25%) of Shardwurm Breath. The partial damage also matched the Kunark logic and not the post-Sept 2002 logic.

PvP would have been dramatically impacted by the change to a 0-200 resist scale, so I went looking for posts made by PvP players and I found them.

Here are some comments made right after the September 4 2002 patch:

Thread title: Resist changes

"Bards can pvp at 55 again. People with 120+mr aren't invincible to me anymore. I engaged 6 people in about 20 minutes and dropped all of them. Slow/snare is USEFUL! YAY! And of course, the best thing about this is that the people with crappy low resist no drop gear get their butts totally handed to them every time now." (09/04/02)

"I GOT MEZED YESTERDAY FOR TEH FIRST TIME IN LIKE 8 MONTHS!" (09/06/02)
https://web.archive.org/web/20031127...b=5&o=&fpart=1

Thread title: verant has to change resists back

"As a warrior I am going to get owned by all classes now...including paladins and rangers. With gear on all my resists were well over 100, which I don't think is bad for a pure melee" (09/05/02)

"yea these resists are fucked up i get snared easy as hell with 122 mr on my sk, same with my wiz thats got 112 mr i meant wtf how am i sposed to get my mr to fuckin 250! such bullshit i really hope they change it back" (09/05/02)

"i was snared for the first time in months with a 141 MR i was shocked and it was some shity ranger" (09/06/02)
https://web.archive.org/web/20031127...b=5&o=&fpart=1


I also found some great Casters Realm threads from 2000 about players who did resist tests to find out the effectiveness of charisma on mez spells. This first guy did tests at 25 MR and 80 MR by casting on a second player. The resist rates were expected using the 0-99 scale:
https://web.archive.org/web/20001018...ML/002086.html

Another guy mezed himself at 25 MR, 50 MR, and 99 MR. The results were as expected using the 0-99 scale. (note that CHA will reduce resist rates a bit, thus the resist rate is not exactly equal to the resist value in these tests) He also did PvE mez tests on a guard NPC, and the reduction in resist rates from Tashania being applied agreed with a 0-99 roll.
https://web.archive.org/web/20020816...c&f=9&t=003257

Note: the PvP resist scale was modified shortly after September 4 2002 which I will explain in a later section.


The Level Difference Resist Floor

The second most significant discovery in the decompiles is the existence of a level difference resist floor which was removed in the September 4 2002 patch and applies to virtually all spells. This floor is similar to the tick save floor which I discussed in another thread. Spells with tick saves do a periodic resistance check and the reason why charm for example can never be guaranteed to last the full duration is because the magic resist is floored to a minimum value which is always above zero. This level difference floor cannot be debuffed under like tick saves, meaning it was not possible to debuff resists down to zero in classic EQ, meaning even debuffed level one newbie area mobs could resist spells from level 50s. This is not the case post Sept 2002 where effective resists can be and very often are zero after debuffs and level difference.

Some spells did ignore this floor however. Lifetaps, lures and unresistable spells were hardcoded to skip the final resist roll entirely thus were not subjected to the floor. Certain DoT spells used the partial damage resist scale even though they were essentially debuffs and this allowed them to hit through the floor because even when failing the roll the partial damage math allowed the spell to land. (Druid magic DoTs and Necro fire DoTs)

For NPC targets, the floor was computed like this:

level_diff = target_level - caster_level

if (level_diff > -11 and target_level > 14 and final_resist < 10) then
	final_resist = 10
end
if (level_diff < -20 or target_level < 15) then
	floor = 2
else
	floor = 5
end

if (final_resist < floor) then
	final_resist = floor
end

Which means: mobs within 10 levels of the caster (except newbie levels, so the vast majority of dark blues) and all NPCs above dark blues had a floor of 10. Most greens had a floor of 2. Stuff between had a floor of 5. Since the rolls were 0-99 and the comparison used a < instead of <= this means that the actual resist rates were 11%, 6% and 3%. (I discuss roll logic in more detail in a later section)

For player/client targets, the floor was always 1.

This is a controversial discovery so I realize that ample evidence is required to convince people. Part of EQ's original ethos was to not have guarantees, so a resist floor makes perfect sense to have existed. It shouldn't be that controversial but players hate nerfs. The following is log file and old user comment evidence of this floor.

We do have pre-Sept 2002 era logs to examine. Finding proof in these logs isn't difficult. I still have some of my own logs of my wizard casting AoE spells on NPCs low enough in level that the effective resist on them should be zero without a floor, but resists are seen. One case in particular was when I was AoEing mobs in the Fungus Grove zone, casting AoEs on mushrooms and dregs. Since AoE spells were used it provides a lot of spell hits. The resist rates and partial damage values matched the Kunark client spell resist logic. Dregs have a level range of 49 to 53, so most dregs would end up having a 10 resist floor, and the resists I saw in the log showed dregs resisting at a higher rate than the sub level 50 mushrooms, and the partial damage hits showed dregs having resist values of 10 and 5 as expected. This alone is quite irrefutable although my logs aren't public.

You need not take my word for this. You can download old 2001 logs from the tipa16384 archive (https://github.com/tipa16384/harcour.../tree/main/DSR) and you will find her doing quad kites in Cobalt Scar on a mid 50s druid, and she gets snare resists on the wyverns.

Here is also a case of her level 55 druid getting a full Ensnare resist on a level 12 or under NPC in Crushbone: (she had an amusing snare macro)

File: etha_log_021502.txt
[Mon Dec 24 04:22:19 2001] You begin casting Ensnare.
[Mon Dec 24 04:22:19 2001] You say, 'Hopefully, orc legionnaire is snared now.'
[Mon Dec 24 04:22:21 2001] Your target resisted the Ensnare spell.
[Mon Dec 24 04:22:24 2001] You emote 'magically ensnares orc legionnaire, bringing it to a crawl!'

again, these aren't hard to find:

[Mon Dec 24 04:26:40 2001] You emote 'magically ensnares orc centurion, bringing it to a crawl!'
[Mon Dec 24 04:26:41 2001] You begin casting Ensnare.
[Mon Dec 24 04:26:41 2001] You say, 'Hopefully, orc centurion is snared now.'
[Mon Dec 24 04:26:42 2001] Your target resisted the Ensnare spell.

A Usenet poster in July 2002 posted an AoE log in Sebilis from a wizard's perspective here: https://groups.google.com/g/alt.game...m/l4m4vFVmMw8J

Notice that the Zephyr of Ice spell was getting partial hits. This spell has and had an innate -10 modifier on it and it's a level 56 spell so he is at least level 56. Combined with level difference he would have overtaken the entire 35 standard cold resist. In fact one of his partial hits was on a zol knight which is the lowest level frog in the zone. The partial damage numbers also agree with effective resist values of 5 and 10.

I found some discussions on an EQ Bard mailing list about bard mezes from early 2000. These bards cast thousands of mez songs on NPCs to get resist rates. The results clearly showed the 3% floor on level 1 greens and the 6% floor on high greens and low dark blues. In one post a bard mentions a "5% cap". This is extremely compelling:
https://dbsanfte.github.io/eq-archiv...tml/14644.html
https://dbsanfte.github.io/eq-archiv...tml/13968.html

"My experience is more with about 20-30 mob pulls than 50, but I seem to get about 10% resists. Ie, for each cast of stun, if we have about 25 mobs there, I see one to four resist messages, usually" (Jul 22, 2002)
https://groups.google.com/g/alt.game...m/waylPHHZsv8J

"Even things that are deep, deep green to him are resisting spells at annoyingly high rates" (April 2002)
https://dbsanfte.github.io/eq-archiv...msg-105695.txt

[Torven]

The Tick Save Resist Floor (Charm, Root, Blind, Fear)

As I mentioned previously, spells with tick save throws also have their own resist floor just for the tick saves, which is 5. This or the level difference floor is used for these spells, whichever is higher. I mention the existence of this floor in another older thread which I had discovered via other means but it's also clearly seen in these decompiles. This floor includes fear and blind which I previously was not sure of. This floor never changed and is still 5 on Live servers, except for fear spells which seem to have lost this floor at some point. (perhaps blind as well but I didn't check)

The level difference floor which was removed in the September 2002 patch had huge implications for spells with tick saves. These spells were simply much worse before September 4 2002 and they broke upwards of four times as frequently as they do using the later era resist logic. Since the rolls were 0-99, a floor of 10 is about the equivalent to a floor of 20 in the post Sept 2002 resist logic. These floors are set just above where the roll is done in the logic so there is no doubt when looking at the decompile how the code flowed.

Tick saves however get a +4 caster level to them, so the 10 MR floor would begin at -6 levels instead of -10 levels difference. This is likely part of why tick saves have this +4 level mod applied to them, so that the 10 resist floor isn't applied to as many dark blues. This +4 would have made a level 43 mob the ideal long-term pet for a level 50 enchanter player. If a level 50 player tried to charm planar mobs, fire/ice giants, or even a higher level bok ghoul knight using the old resist logic, the average duration would have been just 17 ticks because of the 10 resist floor and the break chance per tick would have been four times more frequent compared to the PoP era logic. On the TAKP and Quarm servers, which have PoP era resist logic, this average is 60 ticks assuming they were MR debuffed to the 5 MR tick floor. (using Allure)

Tick saves are not checked every single tick however. They have a preliminary roll done each tick that must succeed before a resist check is done. This preliminary roll is 50% for charm and 75% for root, blind and fear spells. (meaning most ticks will do resist checks for these three) As far as I am aware this has never changed but I can't be certain. These were not found in the decompiles and were told to me by an unnamed source, however the lull break early preliminary roll was found in the clients and this is a 1 in 4 roll like the others, minus charm. Lulls have a tick save throw as well but it doesn't have a floor because this spell line has MR overrides which I explain in a later section.

Lastly the charisma stat did apply to charm tick saves in classic era, according to the decompiles, and it was not limited to enchanters. This was seemingly removed in the September 4 2002 revamp, as some 2003 charm data I found showed no benefit from CHA. (see my other thread) Perhaps because they massively buffed charm at the same time so this removal was a small counter-balance. Enchanters didn't need to debuff charm pets in classic to extend durations in most cases. For more details on tick saves, check my dedicated thread about it.


Tick Resist Floor Evidence Not From Decompiles

I also found an old April 2001 Casters Realm thread titled "CHA and Charm - A numerical study at last" which had some charm duration tests in it. This kind of artifact is as rare as it is valuable and offers compelling evidence for how EQ used to be. The thread can be found here:
https://web.archive.org/web/20010513...04438&go=older

This enchanter was trying to determine if charisma made charms last longer. I can say that on Live servers right now, it does not. But the decompiles of the Kunark clients do show charisma lowering MR on tick saves, but not under the floors. So apparently charisma used to make charm last longer if the target's MR was not already at the MR floor, and this would agree with older Sony dev comments regarding CHA and charm.

His first two tests (at differing CHA amounts) were on an exp giving green con (so almost dark blue) seafury cyclops NPCs in OOT as a level 58. This NPC's MR is 35 and the level mod in this case is -40, so without a floor the MR would be 0. Both his tests would have been at the MR floor of 5 since charm has a floor of 5 and an NPC of that level relative to him would also be 5, meaning charisma would not have been a factor. The average durations for both tests ended up at 26 ticks using a 70 tick max spell, and combined were 50 charms. This agrees with a 5 MR floor at 0-99 scale with a 50% preliminary roll, which in my simulations results in 28.5 ticks average duration. For comparison, the current average duration for Boltran's at the MR floor on TAKP or Quarm is 43 ticks in this scenario.

This guy did more tests after his cyclops tests, and this time on Ssolet Dnaas in Warsliks Woods. This NPC is permarooted which makes doing tests much easier. He did four sets of 25 casts at two different CHA levels and two of the sets were with Resist Magic on the NPC. Since tick saves get a +4 levels to the caster in the algorithm, this would make the MR floor on this mob also 5 in the tests without resist magic. The results also matched the simulations as both tests at two different charisma levels (46 charms) added together ended up about 26.5 ticks average duration.

I tried to go through the limited pre-Sept 2002 logs I have to see if they had useable charm data and they do not. But they do have useable root data. I was able to verify (with high but not absolute certainty) that roots using the old resist system had the same preliminary roll (75%) and the break rates with a 5 MR floor were as expected. You can see this in the tipa16384 archive: the Etha log is of a druid character and she was killing haunted seachests in Cobalt Scar which is always level 40 and has a typical MR of 35. The average duration of a 30 tick root was 15.78 ticks in a sample of 27 when selecting only the first roots cast on the NPCs to remove bias. Simulated root average duration is 16.37 ticks. (using a 0-99 resist roll) I checked a second log that I obtained from a submission by a TAKP player and his 2001 log also agreed with 75%/5.

[Torven]

Resist Caps and Lures

The third most significant discovery in the decompiles is the existence of resist caps. There are a lot of old comments which speculate about a resist cap before Planes of Power, and some of these comments weren't too far off. The caps were applied to the effective resist value, not the absolute resist value, meaning they were applied after the level difference modifier. So the caps would have shifted somewhat relative to the absolute resist value (the number players see in the UI) depending on the level of the attacker casting on them. (this level difference modifier is explained in detail in a later section, which you should read now if you have no familiarity) I say caps plural because there were more than one. I will include lure spells in this section because they are closely related to one of the caps. Note that 'lures' in this context includes Kunark dragon breath spells and various other raid NPC spells and not just the wizard DDs.

The 100 and 99 Hardcaps

Resists were capped at 100 for NPCs, and 99 for players, when defending against non-lure spells after factoring in level difference. This was the case until September 4 2002. This might be hard for people to believe at first because everybody is used to the PoP era system but the decompiles are explicit and the logs back it up. This meant that when fighting Lord Nagafen at level 50, any resists above 111 did nothing, since Nagafen was 5 levels higher this level difference subtracted 12 points from the player's resists. It also meant that when fighting dark blue or green NPCs, your resist level was capped at a value less than 99.

The September 4 '02 patch note said: "Resists matter more for PCs. There are now tangible differences between having 50, 150, and 250 in a given resistance, for example. Resistance buffs, bard songs, and resist gear have actual value, all the way up the line."

The reason why is because resists were capped this low making gear and bard songs useless much of the time. EQ didn't do stats very well and resists weren't implemented very well either.

Keep in mind however that for all-or-nothing spells this cap was almost meaningless. (because the rolls were 0-99) Also most bosses in Kunark, Velious and Luclin had lure AoEs so this cap wouldn't apply against these spells. There were two consequences to this cap: partial damage spells could not be mitigated by players beyond a certain average damage, which was 50%, and all-or-nothing spells will have a 1% chance to always land on players since players cap at 99 and not 100. Sony just didn't want players mitigating spell damage beyond 50% back then. The upside however was that hitting that 50% mitigation level was very easy and thus players could mostly ignore resists and keep their normal gear or focus on HP gear, although this made gearing less interesting.

I checked my old personal logs to see if this 1% chance to always land spells on PCs could be found in them, and I found these cases:

* A single Thunder Blast landed on my warrior out of 61 casts in a Oct 2001 NToV raid. Old screenshots show me with 101 buffless MR back then and I had just cast Aura of Blue Petals on myself right before the cast that landed.

* In a January 2002 log, Shrieker mushrooms in Fungus Grove landed only 3 spells in 336 casts when DR was certainly above 100, as Aura of Black Petals was cast just prior to the spells that landed and level difference granted a +40 resist advantage.


The 151 Resist Immunity Threshold for NPCs

Another significant resist value in classic era was that when casting on NPC targets, there was a threshold at 151 effective resist value, at or above which any spell cast on the NPC would guaranteed resist and no rolls were done. Like the 100/99 cap, this limit is checked after the level difference modifier and debuffs were applied, but it was obviously checked before the NPC's resist was capped at 100. This threshold existed from the start of classic era, as did the 99/100 caps. (they're in the February 1999 client)

This threshold applied to lifetaps and is how lifetaps could resist when they otherwise were always full damage, but (very) old comments suggest lifetaps bypassed this limit in early classic era. Lifetaps may have been unresistable like tash spells back in 1999 but I have no hard evidence of this. They could resist in 2000 for sure.


Lures and the Mythical 255 Hardcap

First let me explain what made a lure spell. In the old spell data, a lure spell was a spell with a negative charisma effect in the first slot. (not including SkunkSpray) This was Sony's hackish way of signaling different resist behavior instead of adding a proper spell field. Back then Sony always assumed that their current expac would be their last one, so they didn't plan for the long haul and took shortcuts. Charisma (with value 0) in spell slots was also used as a spacer so that valid spell effects could be in lower slots; i.e. if charisma with value 0 was in a slot, that slot was ignored. The primary reason to do this was to enable buff stacking.

Sony also hardcoded the Kunark dragon AoEs to be lures without giving those spells a -CHA spell effect. This was done by checking spell ID in the same function that also checked spells for a charisma code. Future dragon AoEs and raid boss spells would use a charisma code, so only the Kunark dragons had their AoEs hardcoded by spell ID.

There were four different charisma codes to denote lure behavior: -3 through -6. -6 and -5 were the hardest to resist (wizard lures, most dragon AoEs) and these had the same resist rate in Kunark even though there were two codes for it, but in Velious this may have changed. -4 was easier to resist and -3 was the easiest. If you check Lucy's spell history, you can see what kind of lure code spells used to have. For example under Lure of Ice it shows: "Removed Slot 1: Lure(5) 2002-09-04"

If you go searching for old claims of a resist cap you will find users saying that resists capped at or wrapped around at 255 due to Sony using an 8 bit variable for it. These claims were false. The partial damage formula requires that the resist variable be larger than 8 bits in the algorithm. The cap for lure spells was so low at 45% that the randomness of it was resulting in users not resisting any AoEs in long streaks even with bard songs and this was giving them crazy notions. You will also find players saying that resists capped around 180-200 and these guys were right, but only for lures.

In 2001 Ester the Tester responded to a player who brought up resists wrapping around to 0 and she shot down the notion explicitly: https://web.archive.org/web/20040927...p/t-10824.html

And another reply where she says, "I can say that we spend a LOT of time with logs, parsers, Excel etc making certain that they do not roll over."
https://web.archive.org/web/20020829...cID=2606.topic


Lures in Kunark

Lure spells were added in Kunark. In old EQ, these spells had their own separate resist roll that bypassed almost every restriction or limitation inside the resist algorithm, and were not merely a negative modifier like post Sept 4 2002 lures are. You might assume that -5 meant reduce the resist by X times 5 before rolling the spell resist check, but this was not the case.

Kunark only had one type of lure spell, and they all behaved in this way: first 100 was subtracted from the resist value. Then the remainder was divided in half and 5 was added to it. Then this result was capped at 45. This was the resist rate of the spell. As usual this was done after the level difference modifier was applied. If the target had less than 100 resist then the spell always landed. The effective resist cap in Kunark for lures and dragon AoEs was 180 + level difference, so 180 on white cons and 192 on the level 65 dragons if the player was level 60. (180 - 100) / 2 + 5 = 45%

Kunark lures:

• Bypassed all previously mentioned caps and guaranteed hit if the target's effective resist was under 100.
• Wizard lures did benefit from the class innate -10 resist modifier.
• Didn't do partial damage. All lure spells were all-or-nothing.
• Could hit anything. Even lifetap immune targets. Wizard lures used the same logic as dragon AoEs, so ice lures could hit otherwise ice immune targets for example.

In mid-Kunark Sony made a new dragon roar spell which had the -6 charisma code for the outdoor dragons. The reason was seemingly because the -5 code only applied to DD spells, and since they needed a lure fear (which is all-or-nothing) they had to make a new code or modify the -5 code to work on all spells instead of just DDs. I'm not sure why they didn't do the latter, but -5 and -6 did the same resist behavior. (again, all the other Kunark dragon AoEs also had this same lure behavior even if they didn't have -5 or -6 codes in their spell data)


Lures in Velious

Sony removed the resist logic from clients in Velious. The last client with it is November 29 2000. So from Velious until September 2002 we have to try and figure out how Sony changed the algorithm without the benefit of decompiles.

Sony added two more charisma codes for Velious. These were added one week before Velious launch and are in the November 29 client. The codes are -3 and -4. They behaved much like the -5/-6 spells did only instead of subtracting 100 and capping at 45, they subtracted less and capped higher. These were to be easier to resist lure spells as you would expect.

-5 & -6 lures subtracted 100 from the resist value and capped the final resist chance at 45%.
-4 lures subtracted 50 from the resist value and capped the final resist chance at 75%.
-3 lures subtracted 25 from the resist value and capped the final resist chance at 85%.

Resists were effectively capped (after level difference mod) at 190 against -4 spells, and 185 against -3 spells. All three divided the remainder by 2 and added 5.

To be clear: that is what the November 29 client showed. A week later Sony changed lures again, and I can't say precisely how, but I will outline the limited available evidence and offer some speculation.

On Velious launch (December 5th) Sony made a change to wizard lures which resulted in them being almost useless on some NPCs. This is a Graffe thread about the drastic change in resist rates:
https://web.archive.org/web/20010523...tart=1&stop=20

A Graffe news page has several Sony rep quotes regarding the changes to lure spells at the time. That page is here:
https://web.archive.org/web/20010306...ive_123100.htm

Abashi at first says lures were supposed to behave like lifetaps and not dragon breaths, and the patch "fixed" them to behave as lifetaps, and this was not mentioned in patch notes because it was "low impact".

A Sony programmer, Roger Uzun, contradicted Absor and said that wizard lures still behave like dragon breath spells, and would not change. He also says quote, "dragon breath saves were adjusted, and that resulted in some few NPCS saving slightly better saves vs certain lures".

This is followed by a Geoff Zatkin comment saying that wizard lures should behave as lifetaps, or even better since wizards get an innate -10 on spells. Uzun however was the server side programmer and probably wrote the logic himself or at least saw it.

Absor responds a day later explaining that the change was intended to force wizards into using the appropriate lure for the target mob, i.e. a fire immune mob should resist fire lures and a cold lure should be used. This makes sense as the Kunark lure logic allows any lure spell to be used on any creature, although even in Kunark using the appropriate lure might still have ended up with higher hit rates depending on the mob's resist levels.

Absor then says that the discussion on lures has made them check the code and they found the real problem with it. The resist rates on lures post Velious launch were too high due to some NPCs getting a saving throw when the NPC was higher in level than the caster, says them, and this was removed to fix the spells. That is a vague statement and doesn't help us much. Nothing like that is seen in the November 29 decompile. Resist rates in Kunark would have been the same for all wizards on high resist targets (45%) regardless of level. This answer also doesn't explain why lures on lower level NPCs like Venril Sathir (level 55) and spite golems were getting resisted more after Velious launch, so this is yet another Sony answer that doesn't make much sense. My best guess would be they added a resist penalty to make lower level wizards resist more since a level 52 wizard would have the same resist rate as a level 60 but they botched it and level 60s were resisting more too.

In other post Absor says this: "Uzun is the server-side programmer. Basically, if anyone knows how this thing works, he's the guy." and "So, perhaps a fire breathing foe will now resist fire Lures a bit better. But it’s resistance to cold Lures wouldn’t have changed." So the intent was seemingly not change the resist rates on targets using the appropriate lure spells, and this is why they didn't have a patch note.
(link: https://web.archive.org/web/20011217...ve/arc43.shtml)

In the Graffe thread linked above, a user posts that the paladin epic proc was landing on VS but wizard lures were not. The paladin epic effect was made into a -4 spell on Velious launch. Another, lower level, wizard says that Enticement of Flame was landing better than the higher level lures. Enticement was also a -4 spell. So it seems the issue that affected the level -5 spells did not affect the -4 spells. Although to make mobs immune to the -3 and -4 spells they would have had to of applied similar restrictions to all three types but perhaps they neglected to do so or didn't care since not many player spells were -4 or -3.

I also noticed something important in the spell data changes. The November 29 2000 patch changed the handful of NPC spells which had CHA -5 to instead use -4, and the result is that -5 was from then on (Velious launch) reserved only for wizard lures. This was probably done so that wizard lures could be made useless on targets with extreme resist values without affecting dragon AoEs, but more could have been done to them. That wizard lures were resisting too much on blue cons for awhile suggests more might have changed. Sadly I have all of three wizard lure casts in my old logs and old comments are also lacking in data so I have virtually nothing to work with to try and figure it out.

I do have ample 2002 logs of CHA -4 spells landing on players however. Logs show the -4 CHA AoEs were all-or-nothing and the resist rates were not higher than the Nov 29 client logic would allow. For example I have a 2002 log of a player raiding Vyemm and Scream of Chaos resisted 60% out of 78 casts. I also found a 67% resist rate of wurm AoEs in 183 casts in one sample of those. CHA -6 Dragon AoEs also were not seen resisting more than the Nov 29 client logic would allow, even with a bard in group for one Warder kill, which showed a 50% resist rate in 12 casts. Old logs (certainly not the ones I have) are not going to be able to realistically tell us if the capped resist rate was higher than the Nov 29 client showed unless the resist rate was way higher, which it isn't. Logs do not show the player's resist value and players back then didn't care as much about their resists.

I also have a log of a cleric doing a raid in Kael in June 2002 (Luclin), and in this raid they fight the Idol. The fight only had a single wizard in it so I can make some third person deductions. The log shows all or almost all 30 lures of lightning and flame connecting after two "uncomfortable" messages. This suggests that the -100 resist portion of lures remained and they still bypassed the resist floor.

In short, the limited log data does not show lures deviating from the November 29 client logic, but the data is insufficient to show possible modest modifications to the November 29 client logic.

I do want to point out here that the raid bosses with CHA -6 spells are highly dependent on these spells to make the encounters challenging. Kunark dragon melee damage is rather weak for example, so if players could easily resist the breaths then the events would be trivial. If the resist cap for dragon breath lures changed in Velious then I don't think it changed very much.

This Graffe forum user says that wizard lures remained all-or-nothing until Sept 4 2002:

"Lures, and spells with a stun component, gained the ability to land partial hits (aka not all-or-nothing) when they redid the resist system last year." (5/16/03)
https://web.archive.org/web/20030725...ID=26511.topic

That suggests to me that wizard lures were still separate from the primary resist logic flow.

On December 19 2000 Sony made the paladin epic weapon proc partial hit, says the patch note, but it kept the CHA -4 on it. Sony seems to have hardcoded some kind of exception for this spell.

When I parsed NPC resists on Live servers, some of them had resists of 1000 or near it. It seems that at some point Sony used 1000 as "immune" although with Live's higher level debuffs and PoP era resist logic lures can now be made to land which is how I know the value is around 1000. Sony likely increased NPC resists with the Sept 2002 patch, but it's possible NPCs had upwards of 1000 resist during Velious. Pre-K classic and Kunark mobs however virtually all had 435 resist as the highest value. (only Vox's CR was higher that I found) So it seems that Sony raised the "immunity" value for NPCs starting in Velious. I think this was done to make lures always resist. Before September 4 2002, 425 would have been more than enough to make targets immune from non-lures, so making later NPCs 1000 only makes sense to make lures resist.

[Torven]

A Resist Softcap?

The September 4 2002 patch note includes this: "Previously, there was only the smallest benefit to having resists over a certain value" which suggests a softcap of some kind. That is the singular piece of evidence I could find for a softcap. There was some speculation of a softcap at the time, but players also speculated of an ATK softcap (which never existed) so they didn't know. A low hardcap of 99 existed from game launch up to Sept 4 2002 for most spells, so if there was some kind of softcap it would have to apply only to lures/dragon spells. Sony may have removed the lure hardcaps at Velious launch and replaced them with softcaps such that lures became useless on 1000 resist targets or some other very high resist value. I have doubts that a softcap existed but the evidence just isn't there to prove or disprove it. That patch note is very little to go by and patch notes are far from proof.

Sony seemed to have wanted to keep resist rates similar to what they were in Kunark since they intentionally didn't make a patch note about the change(s) to lures. Sony also has a history of not wanting to modify older era mechanics. (the Sept 2002 patch is a big exception) So I doubt the Velious lure changes were major. It's conceivable however that Sony put in a softcap for resists at some point since at or near Luclin launch Sony introduced a softcap for AC, but I wouldn't bet on it. (the resist softcap if it existed could have also been a Luclin addition)

The overcap returns for AC in Luclin were small, so I would also expect small returns for resists (like 1/20th or worse) if a softcap existed. Another issue is that there were three kinds of lures which each had their own code blocks. This makes implementing a softcap trickier as you'd either have to duplicate code or not apply it to all lures. Furthermore the CHA -4 lures were already quite easy to resist so applying a softcap on these doesn't really make a lot of sense.

I could find no old comments which asserted that raising resists to very high levels with a bard resulted in significantly higher resist rates. In fact many people still thought that resists did nothing or rolled over after 255, even well into Velious. This indicates to me that resist rates were always somewhere in the neighborhood of 50%, if not remained 45%. If resists are a coin flip then one could easily not resist a single breath against a dragon with 32k HP.

Next I will quote some player claims from the time period for completeness sake.

There is one comment I found which is somewhat contradictory to the others and I'll start with it:

"i'm beginning to believe that there is no cap on resists. for example, me versus phara dar with sanctus in group.
with puretone i was pegging 500 magic resist. buff out to 235 mr in normal resist gear.
regardless, while sanctus was alive i resisted every phara ae. when he lost the song due to a stun i began
failing all my mr checks .. even at level 60 and at 235 magic resist.
also, there is no longer a wrap over effect. 256 no longer wraps you back down to 1." (9/3/01)
https://web.archive.org/web/20010911....topic&index=5

That is also unfortunately the sole comment I found mentioning resists far above 300. This comment is almost useless by itself however because he discusses a single fight vs. a 32k hp mob, and the bard did get stunned with songs on, so the high resists didn't help Mr. bard very much.

Again, if resists are a coin flip then it's expected to see "resists are useless they do nothing" comments and "resists are fine I resisted most of them" comments like so:

"I recently had 250MR (and level 60) when we fought Phara Dar last. I didn't resist a stun. Most of us didn't. Talk about unlucky save rolls." (Jul 9, 2001)
https://groups.google.com/g/alt.game...m/IMMHcQGG0W0J

"Generally with an MR of over 220 at level 60, you can resist most of her AoEs--about 1 in 4 will get through." (Jul 8, 2001) (Phara Dar)
https://groups.google.com/g/alt.game...m/FQwBoXjob-IJ


This comment is somewhat interesting. He says Cursed's AoE almost never resisted until after the Sept 4 2002 patch:

"Later in the evening, I resisted a record number of I think 10 Caustic Mist AEs from Cursed (I think I have, maybe, resited 5 in all the times we've fought him before) with 500 disease resist." (9/5/02)
https://web.archive.org/web/20021120...cID=1220.topic

Caustic Mist is actually a CHA -5 spell. Earlier I mentioned that at Velious launch Sony changed the few boss AoEs with -5 to -4, and only wizard lures were -5. Well, in Luclin, Sony made boss AoEs with -5 again. This sounds like -5s may have been harder to resist than -6s, but the tipa archive has a log with 4 full resists out of 4 casts for the spell Rag`Zhezum's Deathly Embrace, which is also a CHA -5 spell. I just don't have enough logs/data to figure much out.

More comments:

Thread topic: Dragons resists = useless
"After doing VP innumerable times, I've decided that resists vs these dragons really are not very useful.
From now on, I'm going all +STA +HP." (05-18-2001)

"200 MR and I resist 40% of new style dragon fears." (05-31-2001)
https://web.archive.org/web/20010610...ML/000058.html


"Serv is a Bitz thoug, I had 252PR and about 250MR last time we did him and still stunned most of the time" (5/8/01)
"I fight wuoshi with 230p/180+m or so and still get stunned constantly and feared a fair bit." (5/8/01)
https://web.archive.org/web/20011224...cID=3188.topic


"On the 255 roll-over for resists, in my experience having more than 255 is not harmful.
- Last few Hoshkar attempts I've had well over 300 resist disease with a bard (158 unbuffed RD, I drink a
potion anyway in case bard is out of range or I don't get song effect) and was in good shape with the AE.
Every death was by melee. (Still in shock we finally killed him hehe)
- For Xygoz I've had base 150 resist magic and don't quite hit 255 without a bard (215-225). I'm silenced
a lot at 215-255 resist. With a bard in the group, and resist magic well over 255, I resist Xygoz's silence
almost reliably enough to choose when to heal. (If the bard doesn't stop the resist song to juggle songs--
and find out they're silenced now too)
- For Trakanon, with DMF and buffs, if you have a bard it's hard to not go over 255. Past few trak raids
I've been with bards and I don't think I've had to cast a single group heal." (03-06-2001)
https://web.archive.org/web/20040927...p/t-10799.html


"My unbuffed resists can go to the following.
MR-175, CR-186, FR-156,PR-116, DR-147.Against Kunark dragon that serves me well,
and i tend to resist the fire AOE of TOV drakes, wurms dragon, better then the cold AOE.
But when im grouped with a bard with resist song, i dont resist anything(Was fighting talendor with 295 in MR
and got feared everytime).
Im wondering why this is.
is there some number ye may not go over?
I find that if i have around 160-170 buffed in FR, CR, PR, DR i tend to resist alot, the DMG aoe. WIth fear
aoe MR around 190-200 works best. but with a bard that goes down the drain"

"Resists may be capped at 255 (or 200), but they don't roll over. I sit at 262 MR fully buffed, and I resist a lot more than I do unbuffed, and a whole lot more than I would at 7 MR, I'm sure"

"Im not talking about single incident. At one time me and one ranger stood alone against Talendor because we both resisted the fear..well few seconds later he had me crispy with red wine sauce. I have fought talendor around 6 times now, and only time i have resisted the fear, is when i dont have a bard
with me. Gorenaire is however harder to resist it seems, and Severlious(gaddemm stun) also.The fire damage from talendor seems to be unresistable, but im taking different damage every time, so resists help to reduce the damage."

"Resists are based on level a lot. A lvl 60 with worst resists will resist much more then a 55 with better resists. Resists cap at 255. They don't roll over, they just cap. Gore is extremely difficult to resist. Haven't fought the others ones, but i know this ;p. My lvl 60 friend with 255 resists said he was resisting about half the time."
(12-14-2001)
https://web.archive.org/web/20040929...p/t-10918.html


"You do get to a point of dimishing returns on resists, though. In my experience, most resists over 250 work about as well as they are going to work. I haven't noticed myself resisting anything more around 300 that I didn't already resist at 255"

"I am usually over 255 in Cold, Fire and Magic during HoT raids.
I resist or take low partial damage almost every time. Others who meet the 'bare mins' and end up with around 150 buffed get healed alot.
So it definately makes a difference there."
(thread date unknown; Probably Velious era)
https://search.eqarchives.org/search...Findex.html%22


"Personally I feel there is a soft cap, I don't notice a whole lot of difference in resists going from 200 to 300+. But this is just casual observances, I haven't done any hard testing." (9/2/01)
https://web.archive.org/web/20010911....topic&index=5


"3) Get your MR up way up there. Even at 200+, it's hard to resist the stuns. But, it can be done, so drag your bards with you on your next clearing of VP. You can maybe use some "geographics" to your favor, but I don't think you can avoid the AE stun entirely, without very high MR." (Aug 13 2001) (Phara Dar)
https://everquest.allakhazam.com/db/...99773625916336


"last week at a severilous killing i was well over 320 in most resist (buffed - i forgot some gear at bank, hehe) and i didnt resist a single spell from that dragon, while several months ago with less then 200 i was able to resist almost all off the spells (poisen stun and fear)"

"On 2 separate occasions Trak's poison chewed me up. Both times were when a bard was in the group and I had over 270 PR. Other Trak kills I've had significantly lower PR (200ish) and been a lower level but resisted the breath."
(2001 era thread)
https://search.eqarchives.org/search...replyto%3D5%22


"i had a bard grouped with me. My MR was 308, FR 290. At level 57, with resists this high, I still was only resisting about one in 3 waves of either fear or the dot."

"I am not sure if it is true or not but it appears that after you get to 200 on any resists it seems almost useless or your resist rate gets worse. I have seen numerous threads about resists post 200 and from my own experience with resists above 200. When I had a MR at 265 I failed fear 2 of 3 times and went running. With a MR of 178 I was only feared 1 of 3 times."

"Did Sev last night. Ran PR/MR at 230(ish) each. Resisted everything."

"There does seem to be some kind of bug when a bard is playing a selo's drum with the resist songs. For instance, one raid vs Gerenaire and Tal, MR 330 with bard using a selo's drum, the entire level 59-60 group gets repeatedly feared and hit with the AEs. Next raid same group, same levels, but bard not using selo's drum, one group member gets feared, most DoTs resisted, our resists were still in the 300 range."

"Ester the Tester "says" that resists do not roll over after 255...they work just as well. However, after my own testing with Severilous last night, I'm completely convinced beyond doubt that resists roll after after 255. First attempt mr/pr were both over 300, the only spell I resisted was a fear, which was after I had died and come back, full equipment, but buffless. Next attempt I tweaked my gear/bard songs so my mr was 233 and pr 253, resisted about 50% of the stuns and 70% of the fears, which is very good at my low lvl (56)."
(March 26 to April 7 2001 thread)
https://web.archive.org/web/20040927...p/t-10824.html


"The poison is crazy. I'm level 56, done three Trak raids (we've won all three times, btw), and had PR over 300 (thanks new Luclin bard song). His poison still ate me up two of the three times. One time only I completely resisted the poison." (Jan 9th 2002)
https://web.archive.org/web/20031018...=4503&start=75


"Dunno what everyone else thinks but he always seems a heck of a lot easier than Sev to me. With over 255MR/PR (and being lvl 60) Sev still manages to keep me almost perma-stunned or feared, Wuoshi I resist about 75% of his stuns/fears." (3/24/02)
https://web.archive.org/web/20020415....topic&index=5


"We made a couple of attempts on Gorenaire last night with no success. The thing that baffles me though is when I was in range of the bards AE song my Magic Resist was at 294 and Cold resist was at 308 but yet I would still get feared one out of four and was taking some max damage from her AE cold spell." (8/2/02)
https://web.archive.org/web/20020829...icID=544.topic

[Torven]

Partial Damage

PoP and later era EQ has two resist scales: 0-199 and 0-599. All-or-nothing spells use the 0-199 scale and partial damage spells (DDs) use the 0-599 scale. Meaning the spells begin to always full resist after the target's effective resist hits 200 or 600. The average damage on DDs becomes very low well before 600 however. Although if a caster is anywhere from level 30 to 50 and the target is an NPC then the DD scale will vary and be as low as 0-399 due to the partial damage modifiers for level 50 and under casters.

Classic resists have an all-or-nothing scale (0-99) but also the resist caps create a strange region above 99 which is completely flat until the 151 immunity is reached. This allows DD spells to still land even after all-or-nothing spells become immune(ish) for another 50 resist values up until the hard 151 limit. I say this is strange because you would expect a target with 150 resist value to resist more than one with 100 resist value, particularly when resists were more potent back then, but this is not the case.

Here is the partial damage logic from 1999 launch until October 8 2001:

mitigation_pct = (resist_pct * 100 + roll * -100) / resist_pct;		// this formula is used up until Sept 4 2002

if (IsNPC())
{
	if (level_diff > 0 && defender_level > 16) {	// yellows and reds
		mitigation_pct = mitigation_pct + 5;
	}	
	if (defender_level > 29) {
		mitigation_pct = (mitigation_pct - 25) + defender_level;	// gets quite large on the highest level mobs
	}
	if (defender_level < 15) {
		mitigation_pct = mitigation_pct - 5;		// landing on newbie mobs is easier than on player targets
	}
}
if (mitigation_pct < 0) {
	mitigation_pct = 0;
}
if (mitigation_pct > 100) {
	return 100;
}
return mitigation_pct;

resist_pct is the effective resist value and roll is a random number from 0 to 99. Sony's resist algorithm returns the mitigation percentage, which is the inverse of the damage percentage, so the actual damage would be something like: spell_dmg = max_dmg * (100 - mitigation_pct) / 100. Logs show that Sony's servers rounded up using that math, so I'm not precisely sure how they did the final step.

Damage on players is very simple and is computed by that formula without the extra modifiers applied. The modifiers make NPCs targets resist more or less compared to players depending on the NPC's level.

On player targets and NPCs without qualifying modifiers, the above formula will result in a full resist only if, and always if, the roll is 0. Beyond that 1% chance, players could not fully resist DD spells prior to September 4 2002. The spells could still be heavily mitigated down to very little, but the full resist rate was always one percent. This will probably seem odd if you're used to the new resist system.

The maximum a player (and NPCs under level 30) could mitigate non-lure DD spells to was 50% average damage. It's 50% because at max resist (the player cap is 99 remember) the partial damage formula will mitigate the spell damage by about the amount of the roll; i.e. roll a 10, the spell does 11% damage; roll a 50, the spell does 51% damage; roll a 99, the spell does 100%. EQ math is fairly simple.

There are three modifiers for partial damage spells landing on NPCs. The first adds 5% more mitigation on yellow and red con NPCs which are also above level 16. The second adds a large resist bonus to level 30+ NPCs, growing larger the higher level the NPC is, and stacks with the previous modifier. The third reduces the mitigation by 5% for newbie level NPCs.


Partials After The October 8 2001 Patch

Velious was known to be a very melee-centric expansion with caster DPS falling behind the melee DPS. This was in large part due to the increased max hitpoints of NPCs and melee DPS scaling with gear a lot more, but the original resist algorithm was also punishing when casting on very high level targets. Sony addressed this two months prior to Luclin by significantly reducing DD spell mitigation by removing the partial damage modifiers on yellows+reds and on level 30+ NPCs, but only for level 51+ players. Sony also reduced NPC resist values.

Originally Posted by October 8 2001 Patch Note

- The level-based spell resistance bonus inherent in super-high level NPCs has been reduced significantly.

A developer forum post explained it in more detail:

Originally Posted by Abashi on Oct 5 2001

Through our testing we found that many higher level creatures, and especially those creatures that are above 60th level, were typically resisting magical damage to an extent far greater than they should have been. This lead to a couple of classes having their usefulness in these situations either negated or reduced to a pure utility role. As such we’ve made the following changes:

NPCs now have less of a chance to resist any direct damage spell caused by casters above level 50. Super-high level NPCs have received a large reduction in the level-difference bonus they receive to their resists based upon the level of the attacking player character. We’ve increased the effectiveness of resist debuffs against a large number of higher level NPCs in regard to damage spells being cast upon them. We’ve also reduced the resistances on a wide range of NPCs, especially for NPCs in Velious.

I don't know what "increased the effectiveness of resist debuffs against a large number of higher level NPCs" is referring to. Resist debuffs always reduced by the same amounts as far as I'm aware. (PvP aside)

Prathun's 2010 spell resist pseudocode shows the modifiers being limited to levels 50 and under:

Partial resist modifier is set to ((150 * (resist chance - roll)) / resist chance). 
If target is a non-mercenary NPC...
	If target is higher level than caster, and target is at least level 17, and caster is level 50 or below, add 5 to partial resist modifier.
	If target is at least level 30 and caster is level 50 or below, add (casterlevel - 25) to partial resist modifier.
	If target's level is less than 15, subtract 5 from partial resist modifier.

My old logs confirm that the modifiers were gone after that patch for my level 60 wizard which I just happened to have logs of from Oct 2001.

That patch did not remove the DD yellows and reds +resist modifier however. Prathun's pseudocode still has it:

If effect is damage and target is a non-mercenary NPC...
     If target is at least level 67, level difference is set to (66 - caster level) or 0, whichever is greater.
     If target is at least level 17 and level difference is greater than 0, add (2 * level difference) to resist chance.

They might have added that level 67 cap at the time but I have no way to know. There were other points in time where it made sense to add that, and I think Sept 2002 makes more sense because it made raid bosses much easier to land debuffs on and the intent at the time was seemingly to allow damage spells to land easier, not slows.

Removing those two partial damage modifiers for level 51+ casters meant that the damage 51+ players did to NPCs ended up the same as damage done to players, meaning that NPCs could not fully resist DD spells beyond the 1% chance unless it was entirely immune and the average damage players did to even highly resistant NPCs ended up about 50% average damage so it was a significant buff to casters. Before the patch, the most resistant non-immune NPCs would only take about 13% average damage.

I did find a discrepancy with Prathun's pseudocode and the classic logic in regards to the partial damage modifiers. Prathun mentions this: "add (casterlevel - 25) to partial resist modifier". Notice he says the caster's level there instead of the target's level. All of the old clients use target's level there. I strongly suspect that Prathun made an error in his post, because using the caster's level instead of target's level doesn't make much sense as the penalty would get worse as the caster went up in level even while casting on the same level NPCs.




Estimating NPC Resist Values From Spell Damage

Knowing how partial damage is calculated allows us to figure out the target's resist value if enough hits are in the log. Unfortunately I have very few logs from before PoP era so I can only calculate resists for a few NPCs, but if somebody finds old logs at some point they can get a resist estimate by following the instructions I will outline.

First you must understand that there are a limited number of possible partial damage values for a given spell. For any given resist value, only a subset of these values is possible. With enough partial damage hit values, it is possible to determine the target's resist value. I have made a table in a spreadsheet which will calculate every possible partial hit damage for a given spell. With that it is possible to find the resist value that best matches the partial damage numbers seen in an old log file.

Even a single partial hit can tell you that the resist value is over a certain number. For example, if Sunstrike hit for 33 damage, that means the effective resist value is 50 or higher, because 33 is not possible for lower resist values. Note that this is only true for logs from Oct 8 2001 until Sept 3 2002. Also note that you must account for the level difference of the caster and NPC, debuffs, spell resist adjusts (wizards' -10 for example), etc. and reverse apply these to get the NPC's real value.

Using a cell formula of =CEILING.MATH((MIN(MAX(INT((C$3*100+$B4*-100)/C$3), 0), 100)-100)*-1*$F$1/100) where column B is the random roll number and row 3 is the resist value and F1 is the max spell damage, you will get a table of partial damage hits for spells from Oct 8 2001 until Sept 3 2002. In Excel you are able to highlight cells with a specific value using conditional formatting and this makes it easier to find the best resist match. It's more complicated to make a table for damage prior to Oct 8 2001 due to the modifiers and I don't have enough logs of raid content from before that time to get any useful data from.



My October 28 2001 log has AoE damage on Fearplane mobs in it. I had parsed these NPCs on Live years ago, but I can use this log to verify my findings. The expected resist values for a level 60 wizard casting Jyll's Wave of Heat on most of these NPCs should be 10 or 5, which are the floors I mentioned previously, as level difference should give a me -40 and the spell itself another -10, and most of the NPCs in the zone parsed to the typical fire resist of 35 on Live servers. The random level range of these NPCs is 48-52, so 3 out of 5 of these NPCs will have an effective resist of 10 and the other 2 of out 5 will have an effective resist of 5 due to the resist floors.

[Sun Oct 28 17:59:28 2001] a glare lord was hit by non-melee for 65 points of damage.
[Sun Oct 28 17:59:28 2001] A glare lord is incinerated by an intense wave of heat.
[Sun Oct 28 17:59:29 2001] phoboplasm was hit by non-melee for 195 points of damage.
[Sun Oct 28 17:59:29 2001] Phoboplasm is incinerated by an intense wave of heat.
[Sun Oct 28 17:59:39 2001] a glare lord was hit by non-melee for 519 points of damage.
[Sun Oct 28 17:59:39 2001] A glare lord is incinerated by an intense wave of heat.
[Sun Oct 28 17:59:50 2001] a glare lord was hit by non-melee for 65 points of damage.
[Sun Oct 28 17:59:51 2001] A glare lord is incinerated by an intense wave of heat.

The log shows these partial damage hits. 519 is only possible for a resist value of 5, 10, 15, 20, 24 and gets more common above 24. 65 partial damage is only possible for resists 10, 11, 20 or higher. 195 is possible at 10 resist, 17 resist, 20, 24 and higher. So only having these few partial damage hits, we are able to verify that 10 effective resist (effective meaning after all modifiers are applied) value is likely the correct answer for these casts, and the NPCs' resists are 35 because that's the standard resist value. (more on standard resist values later) The next possibilities would be 60 or 70. If you had another log of a player round level 50 you could determine if the resist rate was 35 or 60 just from eyeballing it. (incidentally I did parse them at 35 when I parsed Live server NPCs)

Amygdalans have a higher MR, FR and CR. I parsed them at 95 on Live servers. For these mobs the level difference modifier is either -40 or -32 since my caster was level 60. Fear mobs have a level range of 48-52, so the level 52 ones would end up with a level modifier of -32.

Jyll's Wave of Heat partial damages on Amygdalan warrior: 52, 150, 279, 318, 389, 558
Jyll's Wave of Heat partial damages on Amygdalan knight: 428, 597
Jyll's Zephyr of Ice partial damages on Amygdalan warrior: 292, 565, 571
Jyll's Zephyr of Ice partial damages on Amygdalan knight: 72, 494

The lowest effective resist value that may produce a partial hit of 318 damage using Wave of Heat is 27. The same is true for 292 and Zephyr of Ice. So we can know that Amygdalans had at or above 69 absolute resist value just from those hits. (27+32+10) 95 absolute resist value would translate to either 45 or 53 effective resist value for these spells, and the data matches this for all hits except 428 and 558. I can't explain why those wouldn't match except if a level 52 one with temperate flux staff debuffed, then it would fit. There were a few other wizards there. 95 still fits the best for the data. The next best fit is 85, but if Sony had modified resists I would think they would have raised it by more than 10 on Sept 4 2002. This is fairly strong evidence that common Fearplane NPCs did not have their resists changed since 2001. (probably never)

[Sat Oct 13 23:23:14 2001] Ymmeln was hit by non-melee for 198 points of damage.
[Sat Oct 13 23:23:14 2001] Ymmeln is caught in a torrent of jagged ice.
[Sat Oct 13 23:23:00 2001] Ymmeln was hit by non-melee for 249 points of damage.
[Sat Oct 13 23:23:00 2001] Ymmeln is caught in a torrent of jagged ice.
[Sat Oct 13 23:23:08 2001] Ymmeln was hit by non-melee for 408 points of damage.
[Sat Oct 13 23:23:08 2001] Ymmeln is struck down by Solists spear of ice.
[Sat Oct 13 23:22:01 2001] Ymmeln was hit by non-melee for 960 points of damage.
[Sat Oct 13 23:22:01 2001] Ymmeln is struck down by Solists spear of ice.

I parsed two of these named HoT drakes on Live, although not this particular one, and they also parsed to about 85 cold resist. This 2001 log shows it was maloed, so that means -45 or -60. Reduce by another -10 because of wizard nukes. The NPC is level 60, so there is no level difference modifier. 15 and 30 effective resist value fits for this and not much else. We would expect the resist to be a multiple of 5 which eliminates everything else under 45. The log also shows 11 full damage casts on it, which is a full damage cast rate of 73%, which more closely matches -45 malo. This log data matches Live's value and indicates that the resist value has not changed since 2001 with relatively high confidence.

I have precious few logs of spells landing on raid content prior to September 2002 otherwise I'd give better examples. But this illustrates how it can be done.

A simple way to get an estimate for a resist is by getting the resist rate of full damage DDs or landed all-or-nothing spells on a mob from a log. Since resist rate = effective resist value in this era, it's straightforward to come up with an MR estimate once you account for level difference and other modifiers. This works on Live servers too but you have to multiply the resist rate by two since the scale is 1-200 instead of 0-99 and this is one way I get resist estimates from Live NPCs. On Live servers you can cast hundreds or even thousands of times in carefully prepared logs, but in older in-era logs your estimates will have a much higher margin of error for obvious reasons.

As an example, I have a 2001 log of my warrior attacking Vulak with a Sceptre of Destruction. I can use the proc resist rate to estimate Vulak's magic resist.

In this log, 24 anarchy procs landed on Vulak. 4 resisted. This is a resist rate of ~14%, which would make the effective MR estimate 14. Now we reverse apply every modifier: -40 for tash, -60 for malosini, +50 for level difference modifier and +20 for damage spell penalty on yellows/reds. This makes the modifier -30, so we add 30 to the 14 = 44 estimated MR. That's the procedure, however bards also kept Occlusion on this Vulak for at least some of the fight which throws the numbers off. The resist floor would keep the resist rate at least 10%, so that floor could have been hit here. These factors make for a bad example but I have so few logs to use. I'd expect Vulak's MR to be somewhere around 35-60 looking at this.

I also happen to have five logs of Lady Vox raids of my wizard from before Kunark. In total there are 29 hits and 16 full resists of the Conflagration spell. 12 were full damage. I parsed Lady Vox's fire resist at 60 points on Live servers a decade ago. I also wrote a script to simulate spell casts, so we can test to see if it matches the old logs. Simulating 60 resist value (wizard DDs get -10 but the yellow+red penalty cancels it out) in this scenario results in a full hit rate of about 17% and a full resist rate of 29%. That is somewhat close to the log results of 27% and 35%, particularly when small differences in resist value change the results quite a bit. The margin of error is large with a sample size of 45. One of the logs was from before wizards got the -10 modifier however and the damage was noticeably worse in that, including 3 of the 16 full resists. Also the resist value might be off by 5 as the parse has a margin of error as well. The results at least do not conflict with the classic era resist logic.

[Torven]

What Qualifies As Partialable In Classic

When spells resist, they're either all-or-nothing, or partialable meaning they may do damage between 100% and zero. Partial spells have an easier time landing but the full damage hit rate is generally the same as all-or-nothing spells.

In the vast majority of pre-K classic and Kunark, partial spells were defined as such:

* A spell with only one effect in it, with that effect being either SE 0 or SE 79.
* A multi-effect spell with with the first effect being SE 0 or SE 79, and the second effect being a dispel. (a hardcode for dragon AoEs)
* Multi-effect Enchanter spells under level 13 which have SE 0 or SE 79 as the first effect. (lets newbie enchanters hit stuff better)

Both of those SEs (SE stands for Spell Effect ID) are used for DDs and heals. SE 79 is used in multi-effect spells with a DD or heal component, such as buffs. Both SEs are also used in DoT spells. This is what gave druid magic DoTs and the Heat Blood line lure-like behavior before Sony put in spell resist modifier field, because they only had to pass a partial resist check to land instead of an all-or-nothing check. Those two DoT lines just had a SE 0 effect and nothing else. The other DoTs had counters or some other effect in them.

Another noteworthy spell is Flame Song of Ro, which is cast by the Queen in Chardok and the Shaman epic quest mob in City of Mist. This had lure-like behavior because it has SE 0 as the only spell effect, like the druid and necro DoTs. As I mentioned previously, DD spells landing on players always had a 1% full resist rate; this meant that it was impossible to resist Flame Song of Ro above a rate of 1 in 100 no matter how much resist you had in classic.

Geoffrey Zatkin in May 1999 made a comment about the level 4 Enchanter spell Suffocating Sphere being made easier to land. That appears to be the time they added this enchanter spells under level 13 exception:

Originally Posted by Geoffrey Zatkin May 1999

Suffocating Sphere was made much harder to resist. As a result they also threw in the chance for damage to be lowered on a successful cast. Probably better for the low levellers, they have more chance to hurt that tree snake now.

In late Kunark (it's in the Nov 15 client but not the Sept 19 client) they added another exception for spells with SE 92 in slot two plus SE 0/79 in slot one. This appears to be a hardcode to allow warrior epic procs to be partial hittable.

I am unaware of any changes or additions to partiality qualification in Velious and Luclin up to September 4, other than the Paladin epic proc which is a lure spell.


Partial Spells After The September 4 2002 Patch (PoP era and beyond)

What constituted a partialable spell changed in the big resist system patch of September 4 2002. Sony wanted more flexibility in designing spells and wanted to make spells with multiple effects that could partially hit, so not long before PoP launched they made it such that any spell with SE 0 or SE 79 as the first valid slot could partially hit, but also added a new spell field to override this. You can find this field in spell databases and it might be called "no partial save" or something similar. For example, if you go to Allakhazam and look up the spell Clinging Darkness, then click on raw spell data, you will find a field called "no_partial_save" and the value is '1'. That kept the spell all-or-nothing even though the first effect is SE 0.

To be clear, 'valid slot' excludes Charisma 0 being used as a spacer, meaning slot 1 might be 'blank' and the SE 0/79 might be in slot 2 and it would still partial hit. SE -2 was also used as blank.

Sony mentioned this partial spells change in the patch notes, but it singles out enchanter spells only. This change however applied to more than enchanter spells. I first noticed this while parsing a Luclin raid boss which was landing spells on me when I should have otherwise been immune from having high resists if the spell were using the 1-200 scale. I need to mention however that I'm not entirely certain what they changed the criteria to. Just from observations I've made it looks as though any spell with SE 0 or SE 79 as the first valid slot seemed to partial hit, assuming the no_partial_save flag is 0. There may be more to it than that.

Originally Posted by September 4 2002 Patch Note

- Enchanter spells that have a hit point component and a stun component can now be partially resisted.

Druid magic DoTs and the Heat Blood line were also given -100 resist modifiers after the September 4 patch, so after that patch they could actually be landed on targets up to 700 effective resist value which is 100 more than typical DD spells can land on. The reason why Sony gave these spells -100 modifiers is because before these spells had a 99% hit rate on anything that wasn't outright immune, and without the -100 modifier the spells would have resisted at a rate of 1% for every 6 resist value, so the resist rate on most things would have gone up considerably without it.


Standard NPC Resist Values

The client decompiles also included the routines which granted PCs and NPCs their base resist values. The same function was seemingly used for both. This mostly verifies what I already knew, but I did learn a couple of important things from it.

The standard NPC resist (I'm making this term up) amount is calculated just like player resists are, minus the class bonuses. (e.g. warrior NPCs do not gain extra MR) NPCs do gain the racial bonuses and penalties however. This means that, for example, troll NPCs have a base fire resist of 5. Most base resists for NPCs however are 25 like players to start.

NPCs get a +10 bonus to resists starting at level 25 that players do not get. I had discovered this years ago but it's clearly in the decompiles and is evidence that NPCs used these resist functions. The function also shows that NPCs will gain resist from worn equipment as well as players.

35 is the standard resist value for magic, cold and fire resist for NPCs at or above level 25. The vast majority of NPCs in the game have this much resist value. The ones that do not are generally raid mobs or mobs with resistances to certain types (e.g. gire giants resist fire) which have additional resists added to them. The standard resist for NPCs under level 25 is 25.

15 is the standard resist value for poison and disease resist. These do not get the +10 at level 25. Interestingly this makes disease and poison spells easier to land and I'm not sure why Sony did this. Perhaps because those spells are mostly all-or-nothing. In my discussions, when I say "standard NPC resist value" I usually mean 35, or 25 for low level NPCs, but technically it can change by race and PR/DR are lower.

If an NPC has a resist value higher than standard then it indicates that extra resist was added outside of this base resist function. When I parsed NPC resists on Live servers, I noticed that a lot of classic era raid NPCs ended up around 435 resist and I thought that was strange or possibly indicated that my methods were off. But I now understand why. NPCs have database fields which are something like "extra MR resist" and are added on top of the standard/base resists. So these raid bosses have a database resist value of 400 which then ends up at 435 due to NPCs running the same GetResist() functions that players use.

Knowing that allows us to better estimate NPC resist values. Parsing NPC resists results in an estimate with a margin of error. If the result is near a number like 85, 185, 335, 435 etc. then we can probably assume that those are the actual values, because they would be 35+50, 35+150, 300+35, 400+35.

435 (or +400 if you will) was the highest resist value I've parsed on classic and Kunark era raid NPCs, other than Vox which was probably increased later at some point. That value seems to have been used as 'immune' in that era but this may have been increased on September 4 2002, which I suspect happened and it may have been 335 (or something else) prior.


Changes Sony Made to NPC Resists Over Time

There are known cases of Sony having selectively modified the resist values of certain NPCs, although the details are little known.

During the Velious expansion Sony reduced NPC resists in at least two patches. This expansion was very melee-centric and Sony had to make adjustments so casters were more competitive.

Originally Posted by April 17 2001 Patch Note

- We have reduced resistances to some spell types on some NPCs in Sky Shrine and the Tower of Frozen Shadow. This is the beginning of our overview of the resistances of NPCs in Velious.

Sony also reduced NPC resists in the October 8 2001 patch. Abashi said this in a Developer's Corner post at the time: "We’ve also reduced the resistances on a wide range of NPCs, especially for NPCs in Velious" although the patch note merely says "several NPCs". Part of the reason for this was because Sony added immunity flags for for certain spell effects, e.g. slow, so they could lower magic resist on bosses that were intended to be immune to these effects.

Just about everything if not everything that is immune to slow in that era parsed with an MR low enough for spells to hit (at least after debuffs), so we can assume that all of these had their MR reduced from something like 335 down to a lower amount. This is at least a dozen mobs and includes Tormax, Vindicator, Yelinak etc. Kunark and older NPCs seemed to have kept their old MR immune status and I can't think of one that didn't. Beyond that it's pretty much impossible for me to know what NPCs they reduced resists (i.e. cold and fire resist) on in this patch so unfortunately we'll probably be kept in the dark on this forever, although some old user comments might give clues to a handful of NPCs.

I did find one old comment about this patch that I think is worthy of quoting. He/she suggests that MR was only changed on mobs that were flagged slow immune and this sounds right to me:

Originally Posted by Player Comment From Early Luclin Era

First the October resist patch was done after severals casters class complain about their dmg output. Only wizards with DB was able to do a significant Dmg to dragons.

In this patch IV reduiced resist check on fire and cold on most of the mobs in ToV ( Normals drakes, normal Vurms , Dragons).

They also reduiced resist check on magic for all the mobs who was 100% mr and they added a new concept (Mobs immune to slow). For all the dragons who were already slowable they DON'T changed the magic resist. (dagarn was one of those, he have the same MR pre and post patch).

In all the post you are making lately you seam to say , NToV was hell before this patch and a piece of cake after. You seam to say that it was not possible to slow any of those NToV Dragons.It is not true. Kreizen Eachen Ikatiar are the only dragons it is and it was not able to slow. About Vyemm it is not possible to slow him but it is not since the resist patch but since another and recent one.

NToV is almost the same Pre and Post patch. The only difference is that mage and druids can be effectives Dmg dealers .

https://web.archive.org/web/20020319...cID=2282.topic

It's also very likely that Sony increased NPC resists with the big September 4 2002 patch which doubled the resist roll. The reason is simply because it makes landing spells much, much easier if you double the roll but leave resists the same.

The first altered NPCs I noticed where in Halls of Testing. I had parsed Temple of Veeshan trash NPCs on Live servers and their MR ended up at 185 for almost all of them. If these were 185 MR when spell resists had a 0-99 roll, then landing slow on them would have required malo, tash and occlusion, and one of my old 2001 logs shows that tash+malo was sufficient to land slows. They were however still getting resists after malo+tash which would rule out +100, so 135 pre-patch MR on these seems very plausible. It could have been somewhat more, like +60, but we're not realistically going to be able to narrow it down further without more logs turning up.

A peculiarity I discovered when I was parsing NPCs is the 435 resist values found on classic and Kunark raid NPCs. 435 is actually way higher than is required to make NPCs immune to spells in the old resist system. The immunity threshold is 151, and with unresistable malo + tash that's -85. Occlusion is a Velious song. 335 would have been more than enough to ensure immunity during Kunark and even Velious, even with a -40 level advantage. One problem with leaving them at 335 (if they were 335) would be that non-lure nukes would be able to hit these NPCs decently due to the new 600 scale, which is much larger than the previous 151 limit. I think there is a reasonable chance Sony raised the resists on these raid mobs to make non-lures not land well, then gave wizard lures large negative modifiers to allow them to hit. Wizard lures are -300 after all which is twice as large as a typical NPC AoE lure of -150. On the other hand, lots of Velious trash have 435 cold resist, and it seems somewhat unlikely to me that they'd have edited all those NPCs, so this theory is a bit flimsy and perhaps Sony always had them at 435.

Unfortunately Sony having modified NPC resists like this makes gating content on the emulators difficult if the old resist system were to be put in. It is however very important to look through and adjust NPC resist values downward where it looks likely to have been raised by Sony in the September 4 patch, otherwise stuff will be unslowable and resist far too much. I believe it most likely that Sony went back and raised resists by hand and did not do it algorithmically, which means to be accurate we must do the same, if the old resist system is used. Given that Sony completely neglected to apply no_partial flags to CHA 4 lures, I don't think Sony was particularly thorough about adjusting resists on NPCs either.

Velious Raid Boss Slowability

Slowability of raid targets is by far the most important consideration when adjusting resists, and is the most likely topic that would produce results when searching in old commentary. I believe the available data agrees with my hypothesis that resists were raised by up to 100. I parsed Velious NPCs for resists on Live servers:

Klandicar and Zlandicar have 235 MR
ST Warders have about 255 MR except Hraashna which has about 80. (these have a wider margin of error)
Dagarn the Destroyer has 255
Sontalak 195
Aaryonar 225
Lord Feshlak 195
Lady Mirenilla 210
Dozekar the Cursed 190
The Idol of Rallos Zek 245
Wuoshi 255
The Statue of Rallos Zek 260

Dagarn was known for being hard to slow. I parsed his MR on Live thoroughly to make certain it was 255. Because the resist roll increased from 0-99 to 0-199, the most obvious thing for Sony to have done is increase MR by 100 to maintain his hard-to-slow status. Lets assume they did that. Subtract 100 and you get 155 theoretical old EQ set resist for the NPC. Add 50 for level difference because it is level 70, the effective resist becomes 205 for level 60 players. Subtract 113 from debuffs (Malo, Tash, Occlusion), you get 92 effective MR and a 7% chance to land slow. This seems correct, and if the MR were any different then Dagarn would either be unslowable or easy to slow. I think this is fairly good evidence for my theory that Sony added (up to) 100 points of resist to certain NPCs on Sept 4 2002.

I found this old post regarding the Statue:

Didnt have malo/mala last night...so I couldnt do it. Tash, puretone occlusion, malosini bounced 10+ times....after 5-6 mins I FINALLY got malosini to land...at that point clerics were close to oom and people were dropping like flies...after I got malosini to land I canni'd up just enuf mana for a turgurs...bounced.

Done the statue before, had malo and it seemed easy as pie.

https://web.archive.org/web/20050501...dex.php/t-1057

Subtract 100 points from Statue's Live MR, you get 160. Subtract Tash and Occlusion and the MR becomes 92, which results in a 7% chance to land spells. Most (but not all) of the mobs I list above were probably given 100 MR, and their other resists were also likely elevated.

Aaryonar is level 66, so the level difference modifier would be +18 MR for him vs. a level 60 caster instead of +50. So the effective MR would be 125+18=143 in his case. The resist rate (with malo and not malosini) would only be 31% after debuffs. This seems too low; old comments mentioning slowing him being reasonably difficult. I think his resists were increased by 50 instead of 100. The other NToV dragons have even less MR than Aaryonar, and after debuffs their resist level would be at the floor if you subtracted 100, so I think all the NToV dragons gained 50 instead of 100. Their secondary resists tend to agree with this as well.

NPCs can wear the items on their loot tables, but not always. Sony's content developers had the option of selecting which drops could be worn by the NPC and which couldn't. For example the Statue of Rallos Zek will never equip the Reaver but he will equip his one-handers which can make him quad attack. I parsed Aaryonar's MR twice and the results indicated that he gained 10 MR when he dropped his neck item. (the 2nd parse ended up at 235) This is a tricky thing to try and figure out and particularly for the First Brood dragons since they always drop a resist neck item. I did find some old commentary that Klandicar was sometimes hard to slow, which could suggest that he gained MR from wearing the armor on his loot table and Sontalak for sure could equip one of his weapons because logs show this. If Dagarn wore his robe he would become unslowable but I did not find commentary mentioning this anywhere. The Dagarn I parsed did not drop the robe. Other than Aary I did not check the loot of the other mobs to have any idea what they had.

Three of the ST warders also parsed to about 255 MR and they are the same level as Dagarn. Old webpages were not unanimous on their slowability but I think generally considered them unslowable. I have a few logs of Warder fights in 2001 that were entirely unslowed. This actually makes sense if you duplicate the Dagarn results, resulting in a 7% chance to land slow before you account for equipped loot. Warders were known to equip their loot, and primals have MR on them. This would be enough to make them unslowable unless the bard proc exploit were done.

Incidentally Cazic Thule after the Plane of Fear revamp in March 2001 was slowable for a couple of months before Sony increased his MR to an unslowable amount. They later applied the slow immunity flag on him and lowered the MR for magic nukes to hit.