Cube

Cube is a floating island housing Demons of Tartarus.

Description
Serving as home to Mages of Tartarus, Cube is a massive, buoyant cubed-island that harbors several rocky terrains spread about on its surface. The largest structure is, undoubtedly, one of its many landscapes accommodating Tartarus' headquarters.

Due to its ability to float about freely, Cube's location is anonymous to many, including the Magic Council.

It has been noted that when Face activates, Cube shakes violently as indication to the Magic weapon's awaking.

Trivia

 * The Kanji for "Cube" reads Heades Island.