Buddha
From Record Of Fantasy Adventure Venture
A buddha is an individual who has ended all his suffering and achieved Nirvana, or spiritual enlightenment (not to be confused with Nirvana.
The first such Buddha was Siddhartha Gautama, considered by most Buddhists as the founder of teachings referred to as Buddhism. Kai said he was most likely trapped in a human shell in the 5th or 6th century BC before ending his suffering.
According to Kai, he's considered the Supreme Buddha of this age. That'll probably be important later somehow.