Zero Ikkaku Senkin Game

A survival game takes place at Dream Kingdom, an amusement park which is under construction. The challengers risk their lives to win the game and 100 billion yen. Ukai Zero (Kato Shigeaki) joins this bitter survival game. A non-regular teacher at a cram school for junior high school students in town, his true identity is that of an underground hero who saves the vulnerable who are suffering in modern society. He is a genius gambler who hides behind the appearance of a man who never gets ahead in life, but chooses that others do not lose rather than win himself.

Synopsis: JDrama Weblog