Kooklain is a larval form of demon, only recently having been corrupted. In mortal life, he was a man known for his voracious appetite and general disregard for common sense, temperance, and the welfare of others. His gluttony manifested in his demonic form and in known as "The Consumer".
Kooklain is repellant even by demonic standards, and the rest of the infernal entities trapped in the Book of the Damned avoid him at all costs. Partially this is due to his personality, and partially because of the methane sulphur vapors his buoyant gaseous body is constantly emanating.
After being freed from the Book, Kooklian fled southward to the swamps of Foukemire to feed on the luminous rotten detritus of the bog. To avoid moving around and actually foraging for food, Kooklain attempted to sway the local population of the mire and convince them he was a wrathful. hungry god who needed appeasing. The tribe, a reptilian race known as Rexan, were not impressed and drove him into hiding deep in the river bottoms of Foukemire.