So, I'm going to write some lore about how gods work in this fantasy world since the Mad God has become more important to the story than I had originally intended. Each genuine god in this world is merely one facet of the one creator God in this universe. Just as the Christian God is one God in three persons the creator God of this fantasy world is one God in many, many persons. The creator God is indestructible and unstoppable and thus so are his manifestations. 

For each aspect of creation there is a God; there are gods of space, time, matter, chaos, order, light, darkness, good, evil, fire, water, and every thing in existence. Perhaps no god however is more terrifying than the Mad God who in common usage is called Loki a name that comes from the tongue of the Norns (Hrothgar's race). Loki is the god of madness, dementia, mania, and utter chaos (different from the other God of chaos which represents entropy rather than the type of nonsense and insanity represented by Loki). He lives in a sphere of existence in the spiritual plane called the Mad Hell (different from the actual hell of fire and brimstone run by the god of evil and the seven demon lords). The Mad Hell is a land where nothing makes sense... and that's really the best description I can give of the place. 

It is always changing, always nonsensical, always sinister and dangerous. No normal mortal can enter the realm without slowly being driven stark raving mad, and those who are mad are often brought to this realm upon death. The Mad God is also the God of the darker parts of insanity which include sociopathy and sadism, and many Jeffery Dahmer types end up here instead of the 666 Hells. The Mad God is a God with sinister purposes; his goal is to gain dominion over the other personalities of the creator and drive all creation mad. He is a corrupter driving men insane from his realm and gathering followers in his cult from all races be it elf, human, dwarf, lizard, goblin, orc, tree person, insane monsters, what have you.

His followers in the cult of insanity aim to corrupt the world and make it a more insane place causing horror, death, and disorder wherever they go. They often aim to drive mortals insane either by ruining there lives and torturing them or by trapping their souls in the Mad Hell and driving them insane that way. Their ultimate goal is to expand the Mad Hell into all creation unitl all of creation is the Mad Hell ruled by the one monotheistic Mad God.