Tozu

The self-declared host of the Killing Game, Headmaster Tozu proclaims that he will bring salvation and redemption to all of the students attending Eden's Garden Academy. Despite his volatile demeanour, Tozu demonstrates surprising restraint when orchestrating the procedures of the killing game, almost as if his twisted rules have structure and reason behind them. From what can be inferenced, there is definitely a man behind the mask.

[From official description]