High-upper level demon.
He is a possessor.
He was vanquished thousands of years ago and became a Marfa. His Marfa was guided to a specific host Ollie, Ollie was rescued but Gray never let go of the betrayal. He is scheming to take over the throne, however possible.
Gray causes a lot of trouble by possessing his victims often turning them evil or destroying them for fun and watching their lives collapse.