TrinityCore/TrinityCore — comment on commit 82fa5c97d64e9862787295917dd4ef9bfdeb5d33
File: src/server/scripts/Northrend/FrozenHalls/ForgeOfSouls/boss_devourer_of_souls.cpp line 158
By DDuarte:

Spawned by instance (with no summoner) because 1) Devourer will despawn all summons on Reset and 2) the summoned npc got no UNIT_FIELD_SUMMONEDBY (nor CREATEDBY, nor SUMMON)