The Mbwiru Eikura, roughly translated as "the Unformed Land," and sometimes called the "Spirit World," is an otherworldly realm, according to the Umbaru. It is the central tenet of their belief system, the belief that the mortal realm is merely a veil for the true reality that is the Unformed Land. It is through the Witch Doctors that the Umbaru gain insight into the realm, who can purportedly see and experience it, in a state they call the Ghost Trance. They believe that every being senses the Unformed Land, even if they do not know it. It has been demonstrated that (supposedly) being severed from this connection results in excrutiating pain.
According to the Umbaru, gods dwell within this realm, their life force flowing from the Unformed Land into Sanctuary (it has been said that a 'thread' flows from the Unformed Land into all living things). Thus, the Umbaru hold ceremonies involving ritual sacrifice to keep this life force flowing. Among these gods is Giyua, who is said to greet the spirits of the departed once they enter the realm.
The gods aside, the denizens of the land are mischievous and drawn to power, always seeking to intrude upon the mortal world, but fail to stay for long. An Umbaru priest once crossed into the realm, but returned as a Phantasm (and was subsequently slain).