The Phantomhive family has, for years, been well known for making toys and sweets for small children. However, they are also the Queen's watchdogs; the Phantomhive family keeps an eye on black market dealings in ways that Scotland Yard isn't able to. Ciel Phantomhive is the heir to this legacy.
Until the age of 10, he lived a normal life, with his father, his mother, and the family dog. However, on his tenth birthday, the mansion caught on fire; his parents were killed, and he went missing for a month, only to return with his smile dimmed and his new butler, Sebastian Michaelis, in tow... and a demonic contract in his right eye binding Sebastian to obey his commands.
Ciel is engaged to his cousin, Elizabeth Middleford, and lives with his five servants. Despite his young age, he runs the family company, and as such is quite busy much of the time... though he still finds time to go out investigating dubious legal matters.
At his tender age, the young earl is far more composed and mature than would be expected. He remains distant from others, aloof, preferring to spend his time on work for the company. Aside from his interest in (and incredible skill at) games, he's nigh untouchable. Or so he would have people think. Underneath that clever, bratty shell, underneath the protestations that he has no interest in childish things, Ciel is very much a hurt little boy. He's selfish, not able to fully empathize with people, and he's quite contrary to the point of pushing away things that he doesn't understand because he doesn't want to seem weak, but he cares more deeply about people than he will ever admit.
Earl Ciel Phantomhive (シエル・ファントムハイヴ Shieru Fantomuhaibu?) born on December 14, 1875 is the business-savvy, egotistical 12-year-old (13-year-old as of chapter 14) and the head of the English Phantomhive noble family after the deaths of his parents, Lord Vincent Phantomhive and Lady Rachel Phantomhive. He runs the Funtom Company, which manufactures toys and sweets, with the later addition of a food branch after winning a Royal Warrant. His right eye, which is usually covered with a black eye patch, bears a pentacle, the sign of the Faustian contract he made with the demon Sebastian. Sebastian says that the mark on Ciel is proof of their contract. He also says that demons mark their prey so that they can locate them.
After his parents' deaths and prior to meeting Sebastian, he was a slave and a sacrifice in a cult ritual. During one particular instance where Ciel was being tortured, his hatred for his torturers summoned Sebastian. He then commanded the demon to kill all the people in the room. During his time as a slave, a mark was burned into his back. He does not want anyone to see this mark and appears to not enjoy physical contact, though he tolerates Sebastian and does not complain when the demon picks him up or holds him.
He is usually portrayed as emotionless, un-childlike, though he occasionally expresses concern for the well-being of the few close to him; Sebastian is not one of those people. He sometimes portrays himself as a happy person, but soon returns to his true self. He is a little close to his cousin and fiancée Elizabeth, seeing her as an annoying cute friend, the marriage was arranged, though Ciel is not so fond of Elizabeth that way other than just family. Before the loss of his parents, Ciel seemed to be a happy childlike child. Ciel is proficient with the use of guns, keeping a number of concealed guns nearby in order to protect himself. He has asthma, which was inherited from his mother.
At the end of the anime adaptation, with his revenge completed, Ciel's soul is supposedly devoured by Sebastian. Ciel insists that Sebastian make the process as painful as possible so as to "carve the pain of his life into his soul". He is voiced by Miyuki Sawashiro on the first drama CD, Maaya Sakamoto in the anime adaption and second drama CD, and Brina Palencia in the English dub.
In the second TV series, Ciel is resurrected by the end of the first episode by Sebastian using his family ring (which somehow was concealed in a "New Moon Drop" tea box in Alois Trancy's manor). In a later episode, it was shown that Claude, Alois Trancy's butler, had stolen Ciel's soul. Ciel's resurrection is enigmatic - though he remembers Elizabeth and a few other people like Tanaka, Finnian, Mey-Rin, Baldroy, and the Undertaker - he does not seem to remember other people or certain instances. This is highlighted in the third episode when Grell makes an appearance, and Ciel asks Sebastian who Grell is. Ciel also orders Sebastian to make sure his aunt does not know about his mission, unaware that she is dead (Sebastian does not tell him this). However, when he sees Grell's overcoat a vague image of Madame Red comes into his mind, although he dismisses it quickly. It seems the events that transpired in the first season have been forgotten by him. Also, for some unknown reason, in the first episode, Alois Trancy recognizes him when he sees his lifeless body in Sebastian's suitcase and wants to capture him and Sebastian. By the end of the third episode, Ciel becomes aware of the noble house of Trancy, though it seems that Sebastian has not informed him of the events in the first episode. In episode 10, however, Ciel recovers his memories of the first season and orders Sebastian to remain his butler until he could eat his soul. This does not come about as part of the Contract that Alois Trancy strikes with Hannah Annafellows means that Ciel Phantomhive soul is made unattainable to Sebastian Michaelis due to the fact that Ciel has been transformed into a demon.