In the devilish Butler whom Ciel brought back one day he is called Ciels shadow since is always around Ciel

He is incredibly talented for a butler and is fond of cats.
Nobody really know what goes through this butlers mind the only clues are the trademark smile he always has on his face when he is amused.

Sebastian wear gloves that cover the contract that is located on his hand its what binds Ciel and Sebastian.
Sebastian is quite a capable demon able to do almost anything if his master commands it. There are times when he twists his masters orders in his favor.

And i will be Sebastian ^^