Underworld

The Underworld is the dwelling place of Hades. Although it is a part of the Olympus Coliseum, it stands apart from the Coliseum in that it is the entire setting for Hercules's story in Kingdom Hearts II. The Underworld consists of two parts, the Cave of the Dead and the Underworld Caverns. The Underworld is also home to the Underdrome where Sora can take part in tournaments. Many bosses are fought in the Underworld, including Demyx, Pete, Cerberus, and Hades himself.

The Underworld theme music is "The Underworld", and its battle theme is "What Lies Beneath."