Shin Megami Tensei III: Nocturne is a role-playing game for the PlayStation 2, where players assume the role of a high school student embroiled in an apocalyptic event. After meeting his ill teacher, the protagonist receives powers from Lucifer via Magatama and navigates the Vortex World. Players can choose to align with various factions known as Reasons, shaping the future of the world.
In Shin Megami Tensei III: Nocturne, the player takes on the role of a young boy who is caught up in the apocalypse while visiting his sick teacher, Yuko Takao, with his two classmates Chiaki Hayasaka and Isamu Nitta. The player must survive in the Vortex World with the new powers and capabilities given to the protagonist through Magatama obtained from Lucifer. With these powers, the player is given the opportunity to align themselves with a Reason that decides what the world will become.