is the butler of the Phantomhive household and acts as Ciel's bodyguard. Sebastian's appearance is similar to that of Ciel's father; this has been revealed to be the cause of Ciel, who asked the demon to take the form of the previous Earl, Vincent Phantomhive. Sebastian often describes himself through his catchphrase "I am one hell of a butler." (私はあくまで執事ですから, Watashi wa akuma de shitsuji desu kara). The phrase plays on the word "demon" (あくま, akuma) and the phrase "to the end" (あくまで, aku made). It can also translate to "I am a demon and a butler". In Funimation's English translation, this phrase becomes "I am one hell of a butler," which is, obviously, another play on his demonic origins.
Being a butler and a bodyguard are two jobs he is completely devoted to. He follows Ciel's orders faithfully, however, he does not seem to be overly concerned about Ciel's well-being most of the time as he insults and irritates Ciel to see his reaction. However, occasionally he does appear to care about Ciel's well-being, such as in the Noah's Arc Circus arc where he was worried when Ciel had an asthma attack, and again later on when Ciel had a panic attack. He calls Ciel a "brat" who treats his workers rudely. Sebastian is also shown to be obsessed with cats; in chapter 44 of the manga, he is shown to be hiding 15 cats in his room. But in chapter 49 they show, that the cats were found by Sebastian in a rain, when he was doing a task for Ciel, and just couldn't leave them outside. He also appears to love a stray black cat with amber eyes, who occasionally appears near the Phantomhive household or inside the household's garden. Comically the only times he does not follow Ciel's orders is when he sees a cat, too dazed observing it to pay any attention to anything else.