Underworld

Underworld (アンダーワールド) is the subconscious of a human. When a Gate gives in to despair, their Phantom emerges and proceeds to tear down the host's Underworld before destroying the host itself. Able to assume its host's form, the Phantom proceeds to seek out more Gates and place them deep in despair to repeat the cycle.

When a Phantom causes a Gate to fall into despair, Wizard can use the Engage Magic Ring to travel into their Underworld to destroy the new Phantom before it can emerge, stripping the Gate of their magical potential and saving their life. To destroy the Phantom in the Underworld, Wizard requires the assistance of his own Phantom, WizarDragon.
 * After Rinko Daimon was forced into despair by the Phantom Minotauros, Wizard went into her Underworld and destroyed her inner Phantom Jabberwock.
 * After Shunpei Nara was forced into despair by the Phantom Hellhound, Wizard went into his Underworld and destroyed his inner Phantom Cyclops.
 * After Naoki Katayama was forced into despair by the Phantom Gargoyle, Wizard went into his Underworld and destroyed his inner Phantom Jörmungandr.