Eibon is a fictional sorcerer created by Clark Ashton Smith. He first appeared in the short story "The Door to Saturn"
He was a sorcerer and priest of Zhothaqquah (Tsathoggua). He is renowned as the writer of the Book of Eibon, a tome that, among other things, chronicles Eibon's life, and includes his magical formulae and rites of Zhothaqquah. The book is introduced in Smith's tale "Ubbo-Sathla".
Eibon lived in a five-story, five-sided tower made of black gneiss that stood beside the sea on Mhu Thulan. Eibon disappeared shortly after Yhoundeh's premier inquisitor, Morghi, came to his black tower with a writ for his arrest.
When the inquisition came knocking, Eibon fled to Cykranosh (the planet Saturn) through a magic panel given to him by Zhothaqquah. Eibon was never again seen on Earth after that. (When Morghi vanished close on the heels of Eibon, many believed that he was in league with the sorcerer all along and so is largely responsible for the decline in the worship of Yhoundeh.)
Little is known about Eibon's personality. He was reputed to be a capable judge and law giver. He was also fond of poetry and sculpture though none of this survive.
The Book of Eibon is the work of the legendary magician and sage Eibon. Eibon lived towards the beginning of the latter part of the Hyperborean age. His family died when he was very young but the necromancer Zylac took Eibon on as his prodigy after noticing the child's enthusiasm for the magical arts.
After Zylac's death via a magical accident, Eibon left his house and became a wander. He traveled the length and breadth of Hyperborea learning the secrets of the Voormi Shamans (a race many considered mindless at that time), the astrologers of the southern lands and the half mad wizard who dwelt on the slopes of Mount Vormadtih. It was during this period of time when Eibon first embraced the worship of the ancient god Tsathoggua.
Eventually Eibon settled in the northern province of Mhu Thulan and built himself a tower from which he could survey the entire land of Hyperborea on the horizon. By this time Eibon had become reknowned as both a mighty sorcerer and venerable sage. Many sorcerers and other students of the magical arts travelled to Mhu Thulan to seek his wisdom. Even the kings of Hyperborea themselves would occasionally travel there to seek Eibon's council.
Throughout his life Eibon trained many others in the magic he had learned. However the moods and political climate of Hyperborea changed over the years and the toad god Tsathoggua (Eibon's patron deity) fell out of favor. Eventually threat of imminent execution by the priesthood of Yhounde forced Eibon to flee into the Dreamlands of Saturn using a magical gate given to him by Tsathoggua. His apprentice collected his notes, diaries and correspondence and produced a volume known as The Book of Eibon.