Cordelia (Acolyte)

Cordelia's brother Samael Dolion, known primarily as the Acolyte.
He was ordained by the Architects against his will to forever watch over and eventually release the Grimm, a mysterious, shadowy mass that's able to bring about the end of the world.
Once the world ends, the cycle resets and repeats... and the Acolyte has been at this for a very, very long time...