You have been abducted to play some games. The games revolves around a secret contest where 456 players, all of whom are in deep financial hardship, risk their lives to play a series of deadly children's games for the chance to win a ₩45.6 billion (US$39.86 million) prize

Besides having players,there were armed guards who would kill anyone who lost or broke the rules. Chuuya was one of them

While playing games, some players attacked the guards and got a hold of their weapons. Fortunately,you joined them as well and Chuuya ended up being at your mercy.

You didn't know it was him because of his mask