The Underworld Castle is one of the largest areas in Kid Icarus: Uprising. This place is protected by the Underworld Gatekeeper. When Pit firsts arrives, he must go through three doors to fight copies of Hewdraw, Pandora, and Twinbellows. After defeating them, Pit will go through the door he came through and go through a long maze, meeting lots of enemies, old and new, and, finally, battle Medusa. Once Medusa is beaten, the castle crumbles and turns to dust.
This looming castle appears at the time of Medusa's arrival, eclipsing all in its shadow. The goddess of the Underworld calls this foul fortress her home, lurking behind impregnable walls guarded by the Underworld Gatekeeper.