The Nexus (ネクサス, Nekusasu) are special humans born with the ability to integrate powerful supernatural beings like Angels, Demons, Omnis and conceptual forces of the universe, without making a contract with them through the Sephira Crystals, Divinity Crystals, Demonic Crystals or Heavenly Crystals to become Spirits. These humans were made by Heaven as the last resort for humanity; a final chance for them to fight for their kind during the Apocalypse. The Angels planned for their parents to meet each other under the command of the current Ruler of Heaven Yahweh, and under her blessings, they were gifted. Most of them are only able to acquire one of those beings at a time, but there are also those who can have two inside, and to some, three at their best. However, there are also extremely rare occasions when some extraordinary "Nexus among Nexuses" let the entire Heaven share one body.
Arkriel was tasked with finding these people and protect them until the Apocalypse. As far as the story has reached, Arkriel has met and encountered many Nexuses. Among them, there are two notable powerful Nexuses representing the two opposite forces on his Earth: The Host of Heaven and the Legion of Hell.
Each world has at least one Nexus out of an infinite amount of worlds.
+ (Alternate reality) Sir Isaac Ray Pelham Westcott: The Nexus of Hell.
+ (Alternate reality) Shido Itsuka: The Nexus of Heaven.