Kotsuzuka is a Duelist, nicknamed "Ghost" for his use of ghost-like Duel Monsters cards. He took part in the Duelist Kingdom tournament, where he, Takaido, and Satake teamed up with Bandit Keith, who helped them at first, before later turning on them.
He also took part in the Battle City tournament, where he was defeated and killed by Yami Bakura.

(Source: Wikipedia, Yugipedia)