Aethereal

The Aethereal, or "Ethereal", beings are non-corporeal spirit-like creatures that can become parasitic and possess the bodies of other living, and corporeal, creatures. They "develop sentience" when they take the bodies of sentient creatures. Prior to inhabiting a body, the Aethereals exist in something dubbed the "Over-Soul". From there an Aethereal can descend into the physical realm of the Exterior Plane. Aethereals possess exceptional powers, often unique to each one, but all are thought to be able to manipulate Ext by pure willpower. During an earlier age of Ext there were many Aethereals in the world and some were extremely aggressive, conquering lands and murdering people. Eventually a mass purge of all Aethereals, good and bad, forced all of them from the world until Oda Hideyo summoned Skrai into existence.