A mysterious man described as a demon in human form that haunts the high-stakes mahjong tables. Nobody knows his true name, but he has come to be known as "Kai" (傀), a name with the Chinese characters for "Human" (人) and "Demon" (鬼). It is said that once you hear him say the words "Terribly Sorry", it is only a matter of time until your defeat. 

He is a Mukoubuchi; what true, lone-wolf gamblers are called.