Scytheus/The Vault Of The Martyrs
Constructed by Autocthon from the bones of Baeriol of Cascading Hopes and Dreams and Kidhva, the Goddess of Vigilance and later Patron Deity of Martyrs. This "pocket dimension" encases ThatIsWhichIsNot in a sense of complete sensory deprivation. This keeps Its comatose psyche and bound body in the belief that It has won and Creation no longer exists. With Its body pinned by the cold chaos of TheEightFaedoomLances, and Its wings pinned by the inherent authority of TheFiveMajesticStancesOfAllCretion, the illusion of nothingness could be maintained until a more permanent solution could be derived. Unfortunately, with time, The Games of Divinity soon took precedence in all of the Celestial Incarna's hearts. That Is Which Is Not was out of sight and out of mind.
Baeriol of Cascading Hopes and Dreams would use his control over the hopes and desires of all created beings to keep The Seditious Blasphemy docile. Kidhva would forever provide Essence and strength to Baeriol's efforts. For countless millenia, this seemed to work. However, while only half of That Is Which Is Not is the once-Goddess Elimui; half of it is a shard of Oblivion - a Primordial and uncreated being. This half of The Aeternal Abomination weakened Baeriol's magicks over time until It was able to take advantage of the one flaw of Its prison. The one wing that remained unpinned twitched. This movement caused a disturbance in the tranquility of Its imprisonment. After all, if all is erased, how can one feel movement in nothingness? How can one feel at all?
Since then it has been steadily harder, to keep That Is Which Is Not dormant. Providing It with dreams of Apocolypse after Apocolypse have started to ingrain it with an inherent sense of deja vu. And with each stirring, more and more bindings loosen making it harder to maintain the false emptiness the next time around. There's also the matter of the sudden appearance of some unknown being in the Vault. Without word or delay, he removed most of the Faedoom Lances. Then, he performed a ritual ensuring that any further loosened artifacts would immediately disappear from the Vault to random locations. After that, he simply vanished.
The Vault is failing. Because it is a pocket dimension closed off from the rest of Creation, there is no way to request help. The Vault was built expressly with the belief that after the Immortal War, the first order of business would be disposing of the Aeternal Abomination somehow. So, there would be no need for an alarm system. However, that turned out to be an assumption made in bad judgement. And when The Inverted Womb breaks free, Baeriol of Cascading Hopes and Dreams and Kidhva will perish - their symbiotic link sundered. And there will be no more Primordials to construct another Vault.