Homura was born between the humans and the warriors of the Upper heavens. Although he succeeded Nataku Taishi who destroyed Gyumaoh-Bull Satan 500 years ago, he is fed up with utter tranquility and lazy life in the Upper Heavens. He had some relationship with Sanzo and his comrades. He calls them by their names from a previous existence. He is eager to get Sanzo's Sutra of Dark Power. His ultimate ambition seemed to be the creation of a perfect world with Son Goku as a tool, but it is shown near the end of Saiyuki Gensomaden, that he was looking to be defeated by somebody who is worthy of him, Son Goku--the "perfect world" was only a place where he could obtain the most honorable and worthy death. His weapon is a flaming long sword possessing tremendous power. He can wipe out a troop of monsters at one swing. He uses the Power of Spirit, better known as Chi, like Cho Hakkai. He's always seen wearing a pair of handcuffs which serve as his power-limiters, and becomes far stronger when he takes them off. He fought and easily defeated Goku on a number accessions to push into becoming more during Saiyuki Gensomaden, and eventually pushed Goku into growing strong enough to the point where he as able to kill him at the end of Saiyuki Gensomaden.

Source: Wikipedia