Shin Megami Tensei: 20XX Devil's Colosseum (真・女神転生 デビルコロシアム 20XX, Shin Megami Tensei Debiru Korushiamu 20XX) is a cell phone game created as a prequel to Shin Megami Tensei: 20XX. The game tells the history of the Hero before the events of the previous game.
- Japan: April 28th, 2008 (S! Apps)
The game uses the Elemental-Based Combat System, but the races of demons were renamed by their combat type (e.g. instead of "Youki", they are named 戦人, Ikusanin, "Battler"), and the number of party members were reduced to 3. Also the player can experience new features when starting a new game if they can defeat the secret boss.
Two twins (a boy and a girl) are left by their parents in an orphanage called "Silent Night". They grow, and at 14 years old, the girl is possessed by a demon and throws the orphanage into a dark maze, full of monsters. After receiving a COMP by a mysterious man in a wheelchair, the boy travels to rescue his sister and save the orphanage.