Shin Megami Tensei: 20XX Devil's Colosseum

Shin Megami Tensei: 20XX Devil's Colosseum is a cell phone game created as a prequel to Shin Megami Tensei: 20XX. The "Demon EXP" system was implemented in this game, which allows demons to gain EXP and level up.

Profile
The game uses the Elemental-Based Combat System, but the races of demons were renamed by their combat type, e.g. "Brutes" are instead called "Battlers", and the number of party members was reduced to three. There are also new features that can be unlocked when starting a new game if the secret boss is defeated. There is also a full translation of the available online script.

Plot
'Note: This synopsis is written based on the available text which uses a female protagonist. It is possible that the gender of the protagonist is chosen at the beginning.' Two twins (a boy and a girl) are left by Stephen in an orphanage along with a COMP. They grow, and at 14 years old, the boy is possessed by an unknown force and disappears. Seeking out information, the protagonist finds the "Devil's Coliseum" tournament and using it to try to find information on what happened. As the game progresses it is learned that the boy is possessed by YHVH, having set up the tournament in order to find the Messiah and kill them, having decided humanity does not deserve to be saved. Lucifer is fought on Neutral and Law routes and Satan on Neutral and Chaos routes. Every route ends in YHVH giving up on the boy, and the boy dying and the protagonist seeking out Stephen to try to prevent anything like this from happening again. When the compendium is completed, there are 2 emails sent. The first is from Stephen referring to the protagonist as a savior. The second is from the brother, stating that he is losing control of himself, sending a demon to the version of her in the past, telling her to kill him if he completely loses control.