Kai (pronounced Ki, not Kay) is the shortest member of the Capsule biker gang. Though he is normally quiet, Kai can really kick it in gang fights. He is an equal rider to Yamagata. He is the only boy in the gang who lacks a girlfriend, probably because of his height.
Kai hangs around with Yamagata a lot, and appears to be the most affected by his death.
For some reason, he always wears a red tie, even when he's out biking.