Megami Tensei Gaiden: Last Bible II is a role-playing video game series developed by Multimedia Intelligence Transfer, Sega, and Menue, and published by Atlus and Sega for multiple platforms. Players explore the game world and fight monsters in menu-based battles; players can also attempt to recruit monsters to their party, and can fuse two allied monsters into a single new one to try to get stronger monsters.

Ages ago, people lived on what was then known as the Fifth Planet. They were able to use telepathy, teleportation, and telekinesis powers that were once reserved for gods alone. They called the powers Gaia, and adept users were known as Gaia Masters. Despite wielding these powers, the fall of the Fifth Planet forced them to flee to Terra, the Third Planet, to dwell with the beasts. War soon erupted between the humans and beasts. Both sides fought desperately for control over Terra. In the end, there was no victor. The battles ended up leaving the humans and the beasts decimated. The survivors did not have the strength to keep fighting. They no longer fought for control of the planet. They merely struggled to stay alive. 2000 years later...