Seal (World)

The Seal (異界) or the Otherworld (異界), also known as the Underworld (冥界) is a Demi-Material World that overlaps with the Spiritual World such as Elemental Realm and Daemon Realm, in which Ivarage was sealed by Veldanava and where the Aggressors live.

Otherworld is said to be a Parallel World of the Daemon Realm, and can also be accessed through "Underworld Gate".