The Black King appeared at Babel Tower in R2 as a Chess opponent for Lelouch. He also has a reputation as an excellent Chess Player, whether he earned it by his skills or by using illict means is not known. 
Black King of Code Geass


The Black King first appears is shown as a lecherous old man rather than an accomplished Chess Player. Before he met Lelouch, he participated in a questionable game called "Rabbit Hunt", in the game he has successfully managed to capture three of them save for Kallen. He is a believer of Emperor Charles's Ideology where "the strong rule and the weak die" as he considers the Elevens nothing more than slaves. He is also commented by Rolo that King is member of the Mafia. 

Lelouch and King face off in a Chess Match, which King loses to. Instead of facing defeat, King accuses Lelouch that he cheated and got his bodyguards to attack Lelouch and hold him down. The Nobleman then points his gun at Lelouch ready to kill him but the Black Knights begin their operation to recover Zero by assaulting Babel Tower. During the confusion, Kallen kicks King and tries to escape with Lelouch but he runs away with Rolo. The Black King is later killed by the OSI soldiers.