Demogorgon (Dungeons & Dragons)

In the Dungeons & Dragons fantasy role-playing game, Demogorgon is a powerful demon, also called the Prince of Demons. The emnity between Orcus and Demogorgon is legendary. In Gary Gygax's Gord the Rogue series, he is the brother of another demon lord called "Mandrillagon."

Appearance
Demogorgon appears as an 18-foot tall, reptilian (or amphibious) hermaphroditic creature with a tailed, somewhat humanoid form. Two babboon heads sprout his snake-like necks, and his arms end in long tentacles. He can hypnotize with a gaze or drive enemies insane. His whip-like tail has the ability to drain the life energy right out of a living foe. His tentacles cause living creatures to rot away, as if by some sort of rapid leprosy.

Demogorgon in Greyhawk
In the World of Greyhawk campaign setting, Demogorgon sometimes goes by the ancient name "Ahmon-Ibor," or "the Sibilant Beast." He is responsible for corrupting the paladin Sir Kargoth and transforming him and thirteen of his fellow Knight Protectors of the Great Kingdom into Oerth's first death knights.