Sebastian takes on the appearance of a tall, handsome adult with black hair, reddish brown eyes,[3] pale skin, and black fingernails. The back of his left hand contains the mark of his Faustian contract with Ciel Phantomhive. HIs Personality Is: cunning and morally bankrupt, and he has no qualms about lying, cheating, and seducing others to gain the upper hand. He strictly adheres to his demon aesthetics and principles, one of which is not entering into multiple contracts, for he views such as.