Dougan Go

Dougan was assigned as Sanzo's personal attendant way back before the journey west even began. The young boy became infatuated with the priest after he was asked why he was beaten up. Dougan did everything in his power to serve his master Sanzo, until the day that Sanzo left the temple on a mission to save shangra la.
From that day forward Dougan became determined to prove to Sanzo that he would be of use to him on his journey. He fled from the temple, underwent training, and returned years later, only to find that Sanzo was no longer there. Realizing he was left behind again, the young man snapped and ran away once again. He learned of Sanzo's travel companions and yearned to become just like them so that he would possess all of their qualities and he alone could assist Sanzo. He was fiercely loyal like Son Goku, killed a thousand demons in one night and became one himself like Cho Hakkai, and dyed his hair red with the blood of his victims to look like Sha Gojyo.
For years he waited in the castle of the clan he slayed, just waiting for the day when his master Sanzo would return and he could finally show him how powerful he'd become.

Dougan is overly dramatic and seems to spend all of his time making paper airplanes. He took Houran, the daughter of the leader of the clan he slayed, in as his personal slave and used her to lure the Sanzo Ikkou to his mansion. He is defeated at the end, when the shikigami he placed in his body causes a black hole to form, sucking him in.