Rachel Phantomhive

Lady Rachel Phantomhive (レイチェル ファントムハイヴ Reichieru Fantomuhaivu) is the late wife of Vincent Phantomhive and mother to Ciel Phantomhive.

Rachel was shown to be a beautiful woman with long strawberry blond hair and blue eyes. She was described by Angelina to be gentle, extremely beautiful, and someone who never put on airs.
She was an extremely kind individual who cared greatly about her family, as she always worked to cheer Angelina up and include her in the family. She also had a bit of a playful personality, as she once complimented Angelina on her breast size while grabbing them. Like Ciel, she also had asthma, and was part of the reason Angelina worked to become a doctor, as Angelina stated that she would like to cure her asthma. She had a lot of admirable qualities, and was fortunate in marrying a man she loved and having a child with him. Angelina has shown that she is envious of her for these reasons, even after she died. 

Vincent Phantomhive

Earl Vincent Phantomhive (ヴィンセント ファントムハイヴ Vinsento Fantomuhaivu) is the late head of the Phantomhive family, and is who Ciel Phantomhive inherited his titles from.

Vincent was the head of the Phantomhive household and acted as Queen Victoria's watchdog, both titles that Ciel later took over. Tanaka has shown to have worked for the Phantomhive family at least since Vincent's time.
Sometime while he was alive, he hosted a variety of parties that many others nobles attended. When Baron Kelvin attended one of these parties, it is the first time that he encountered Ciel, and he made a continued effort to network with Vincent after that. While Vincent was kind, the others were not, causing Baron Kelvin to believe he had to be more "beautiful" to be accepted by their social circle. As a result, Vincent is indirectly part of the reason for Baron Kelvin's obsession with undergoing plastic surgery and with Ciel.
On Ciel's tenth birthday, Vincent and his wife were killed in a fire, his son was kidnapped, and his manor was burnt to the ground. It seems that the reason for this was related to his work as the queen's watchdog and his control over the underworld. In the anime, his death is directly attributed to Queen Victoria. 

Sebastian Michaelis

Sebastian Michaelis (セバスチャン ミカエリス Sebasuchan Mikaerisu) is the butler of the Phantomhive household. He is also briefly part of the Noah's Ark Circus, where he goes by the stage name Black (ブラック Burakku). Sebastian often describes himself through the phrase "I am one hell of a butler" (私はあくまで執事ですから watashi wa aku made shitsuji desukara). The phrase plays on the word "demon" (あくま akuma) and the phrase "to the end" (あくまで aku made) which can also mean "I am a demon and a butler."

Ciel Phantomhive

Ciel Phantomhive (シエル ファントムハイヴ Shieru Fantomuhaivu) is the head of the Phantomhive noble family. He runs the Funtom Company, which manufactures toys, sweets, and food. His birthday is December 14th, 1875. He is also briefly part of the Noah's Ark Circus, where he goes by the stage name Smile (スマイル Sumairu). "In memory of Ciel Phantomhive, Who died on Aug, 26th 1889, AGED 13 YEARS"