Shin Megami Tensei II is set in the year "20XX", decades after the events of Shin Megami Tensei, where a war between angels and demons was fought. Opposing both sides, a man called the Hero created a world where both Law and Chaos could co-exist, where people had freedom to choose and believe what they wished. In the time between the two games, the world was plagued by disasters, and the air became unbreathable. People flocked to the encapsulated city Tokyo Millennium, which was built atop the ruins of Tokyo, where mutants, fairies and demons live. The city is ruled by followers of the Messian religion in a central unit called the Center, and is divided into districts; the largest one is Valhalla, where people can compete in a gladiator tournament, with the winner gaining citizenship in the luxurious Center, which is out of reach from demons.