Frostmourne (Icecrown Citadel)

SS Icecrown Citadel

The Frostmourne subzone is a spiritual realm inside Frostmourne where a player is transferred into if a player survives the Lich King's Harvest Soul ability. King Terenas' spirit fights with a Spirit Warden inside. Players leave Frostmourne when the Spirit Warden is dead.

The Blades of the Fallen Prince subzone appears to be the continuation of the spiritual realm.