Miaka's girl-and-beer-crazy onii-chan, the viewer's link between the Shi Jin Ten Chi Sho and the real world...

Keisuke is in university majoring in ancient Chinese, or so I have been led to believe by Kristi and Priya. That's why he can read the Chinese characters in the Shi Jin Ten Chi Sho as he follows the adventures of Miaka and her seishi. Anyways, Keisuke is really cool. ^_^ I mean, he sits there in the library reading things about Miaka that I'm sure no brother would like to hear about their younger sister, and yet he totally stands by it. He kind of represents the audience, reacting as we would (or should ^_^) react to the events in the story (awe/shock/sadness etc).