Asteroid M

Asteroid M is a world appearing in Kingdom Hearts: Awakening and is the domain of Magneto.

Setting
Asteroid M is just what it sounds like; an asteroid.

It originated when Magneto's first Gummi Ship crashed into an asteroid with no way to go anywhere. Trapped and afraid, Magneto made the best of it, and developed a way to survive. He built off of the ship into the asteroid, creating a hollow mini planet inside. Now the technology of the planet dives inside the asteroid.

Story
This is the world Laharl, Ceodore, and Ash join after the Johto League. They are frantically searching for Allen, but get separated inside the asteroid.

Trivia

 * This is the only world that allows different playable stories with three protagonists. (The story joins up again after the world is completed)