Muramite Proving Grounds: Mastery of Weaponry (chambersb zone)
 

This encounter involves four NPCs, each susceptible to increased damage from a particular source:

305000 Steelshock - direct damage spells/procs
305001 Hemkai the Ascendant - piercing
305002 Granite Stoneguardian - blunt
305003 Hulking Bazu - slashing

I see the NPCs are in the current database, but I don't recognize anything imparting this type damage weakness, nor does a Perl/lua file exist imparting it. I was wondering if anyone has any information on how this was accompished? Thanks in advance.

There are a number of ways to make an NPC weak/strong verse a melee skill type.

Via quest ModSkillDmgTaken(skillid, amount)
Via spell effects - SE_SkillDamageTaken 197
Via the table npc_spells_effects - using SE_SkillDamgeTaken

Since MPG is an OoW zone, PEQ's DB/quests has no real work done on that zone.