"Lovecraftian" is a term that gets overused, like "Epic", by people who probably don't know what Lovecraft's stories were like.
The only thing that has a 'cosmic horror' from the darkside of the universe (or creature of nightmares, insanity and chaos) vibe is the Flying Sting, and that's only through the backstory given by Peter Spear in the King's Question Companion.
The general decorative motive of Mordack is somewhere between generic D&D necromancer/evil sorcerer, and medieval concepts of hell... Some of the statues may be roughtly mesopotamian, or babylonian/assyrian.
Of course satanic goat (organ)...