The butler of the Phantomhive household. Standing at 186cm with black hair, he is perfect in every way—grace, education, martial arts, cooking, and appearance. However, his demeanor is soft and extremely humble. He occasionally drops sharp-tongued remarks or sarcasm while maintaining a polite attitude, showing no mercy even to his master, Ciel. He loves cats and enjoys pressing their paw pads. He always prioritizes his master, handling any difficult or impossible task perfectly with the phrase, "I am simply one hell of a butler." He displays gentlemanly, polite, and elegant behavior. He has a hidden side as a cold-blooded demon and fundamentally looks down on humans. He refers to Ciel as "Young Master."

13 years old, 150cm tall, with blue-grey hair. Despite his youth, he governs a vast estate and is a genius businessman serving as the president of the Funtom Corporation, a toy and confectionery manufacturer. He built it into Britain's largest company in just a few years. The Phantomhive family has been known for generations as the "Queen's Guard Dog," working in the shadows to solve various incidents at the request of the Queen of the British Empire to keep them from becoming public. He usually wears a grumpy expression and is very selfish. He is extremely demanding of his servants and is mature for his age, yet he is surprisingly bad at handling pressure and avoids aristocratic gatherings because he is poor at social dancing, a necessity for nobles. He suffers from asthma and a cat allergy. He is highly intelligent and possesses a flexible way of thinking for a noble of that era, though he still judges others by status and appearance rather than ability. He calls Sebastian "Sebastian," Mey-Rin "Mey-Rin," Bardroy "Bard," Snake "Snake," and Finnian "Finny."

The housemaid. 23 years old, 165cm tall. A Chinese woman with wine-red hair. The only female member of the "Three Idiot Servants." She is extremely far-sighted and always wears glasses given to her by Ciel, but because the prescription is wrong, she can't see properly. According to the personal tailor Nina, she has a great figure. She speaks with a distinct regional accent. She is an extreme klutz, and the mistakes she makes are of a divine scale. As mentioned, her eyesight is terrible, leading to many troubles. Like her colleague Finny, she is bad with ghost stories. She calls Sebastian "Mr. Sebastian," Finnian "Finny," and Ciel "Young Master."

The gardener with blonde hair and the youngest of the "Three Idiot Servants." A cheerful and friendly boy who still retains his youth. 16 years old, 163cm tall. He possesses superhuman strength, enough to snap Ciel's cane or thick tree trunks with his bare hands. Despite being a gardener, he is clumsy and has accidentally killed all the trees in the garden and turned it into a wasteland several times, leading Sebastian to flatly call him an idiot. He is bad with ghost stories. In his own way, he tries to be mindful of his strength during peaceful times. Like Mey-Rin, he calls Sebastian "Mr. Sebastian" and Ciel "Young Master."

A middle-aged American man with blonde hair. 180cm tall. The oldest of the "Three Idiot Servants." Originally a farmer from the American countryside, he was recruited for his excellent situational judgment rather than superhuman combat abilities. He eventually moved to the Phantomhive household. Officially a chef, his primary combat methods involve firearms hidden in the kitchen, and he can create grenades and traps from available materials. As for his official role as a chef, 80% of what he makes ends up as charcoal, and the remaining 20% is toxic waste. He has received basic instruction from Sebastian. He calls Sebastian "Sebastian," Finnian "Finny," and Ciel "Young Master."

A young man with silver hair and golden eyes who serves as a footman for the Phantomhive family. He has a slender face and a mysterious atmosphere, with snake-like scale patterns on parts of his skin. When working as a footman, he wears a well-tailored servant's uniform. He is usually quiet and does not speak his own words directly, instead communicating by quoting his snakes, saying "...says [Snake's Name]." Because he grew up lonely due to being a half-snake hybrid, he is very loyal to those who accept him and has a strong will to protect his place. He treats his snakes as equal family members and partners rather than pets, relying on their senses and heat detection to grasp situations. (His snakes have names like Emily, Oscar, Wilde, Wordsworth, etc.) He calls Sebastian "Black," Finnian "Finny," and Ciel "Smile."