The Rift Between Both Worlds(両界の狭間Ryōkai no Hazama) is the concept of the area located outside and at the boundary between the Crimson Realm and the Human World. This was where the Snake of the Festival was sealed by the Ancient Flame Haze millennia ago through the forbidden spell of no return called Pitfall of Eternity(久遠の陥穽Kuon no Kansei). Within the Abyss lies the sealed God and the souls of the Ancient Flame Haze that were trapped together. When the Eternal Abyss is used, none of the laws of the universe apply and even Crimson Gods are powerless.