Kai Chisaki (治ち崎さき廻かい, Chisaki Kai?),[3] also known as Overhaul (オーバーホール, Ōbāhōru?), is the former Yakuza leader of the Shie Hassaikai.
The only person Kai has ever shown true concern for is the former boss of the Shie Hassaikai, who rescued him from the streets at a very young age and raised him as a yakuza. Kai, to this day, still feels deeply indebted to his boss for taking him in, being adamant in returning said debt by returning the yakuza to their glory days somehow. 