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 Spooky Palace located and where the Aggressors live.

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