"Master, is it really okay?"
"The contract has been completed, and everything about me is up to you."
"Then, come with me to the world of demons, Ciel."
"What did you say?! Sebastian!"
The noble English Earl Charles Phantomhive entered into a contract with the Demon Emperor Sebastian Michaelis. After the contract ended, the love between master and servant did not end. The Demon Emperor's pets are not easy to mess with!