As the Servamp of Pride, Hugh embodies traits of arrogance and dignity, though his pride is often expressed in a childish manner due to his five-year-old appearance. This creates the impression of a small child trying to act mature and authoritative, often failing in endearingly naïve ways. Despite this, he remains strongly prideful of himself, his Eve, and his identity as a vampire.

Hugh’s speech patterns are noticeably old-fashioned, giving the impression of wisdom beyond his appearance. He is generally calm and collected, displaying extensive knowledge about vampires and Servamps, reflecting his position as the second oldest among them. Nonetheless, his behavior often drifts into immaturity; he becomes easily excited over trivial matters, such as choosing toys from a children’s menu, where he eagerly attempted to take all of them.

He also emphasizes his identity as a “real vampire,” frequently beginning statements with “A real vampire…” to lecture others on proper vampiric behavior. Ironically, Hugh does not always live up to the standards he describes, though he seems unaware of this contradiction. His animal form is a bat, and he openly proclaims his love of blood as part of his meals, further reinforcing traditional vampire traits.

Following a loss of power, Hugh’s personality undergoes a dramatic shift. He adopts the demeanor of an elderly man, complaining about back pain, showing memory lapses, preferring tea, and speaking with the tone of an old man. It is later revealed that this transformation was an elaborate act, as Hugh never lost his powers to begin with.

Hugh is the smallest of the Servamps, with a height of only 2’6” (76 cm), giving him the outward appearance of a young child. He has short black hair, sharp red eyes, and prominent fangs, hallmarks of his vampire nature. Despite his diminutive size, his clothing reflects an elaborate gothic style designed to evoke the image of a dignified vampire. His outfit typically consists of a black suit with red coat-tails, a black cape lined with crimson, and a tall black top hat. He often accessorizes with a monocle and carries a pipe, which he occasionally uses as a walking cane. These items reinforce the old-fashioned elegance that contrasts with his childish body.

His small stature and youthful appearance serve as an ironic counterpoint to his true age, as he is the second oldest among the Servamps. This juxtaposition underscores the duality of his character—ancient wisdom paired with a childlike exterior. In addition to his humanoid form, Hugh shares the common trait of all Servamps in being able to transform into an animal. His animal form is a bat, further tying him to traditional vampire imagery and reinforcing his insistence on being a “real vampire.”

Before becoming a Servamp, Old Child was once a wealthy nobleman named Algernon III, who lived alone in a castle outside a nearby town. Eccentric and reclusive, he was disliked by the townspeople and often wore black clothing, which contributed to his reputation as an outsider. The only person who visited him was a young boy named Hugh. Initially intending to drive the boy away, Algernon eventually allowed Hugh to remain, and over time the two formed a quiet companionship despite having little to converse about. Hugh nicknamed him “The Dark,” as Algernon never revealed his real name.

Algernon eventually died of old age, content in the knowledge that his final days were brightened by the boy’s company. Grief-stricken, Hugh was found wrapped in Algernon’s black cloak. Soon after, The Count, the creator of the Servamps, approached Hugh and granted his wish to revive the old man. Algernon’s soul was placed into Hugh’s young body and transformed into a vampire, since Algernon’s original body was too old to sustain. Realizing he had been manipulated through Hugh’s affection, Algernon was horrified and swore vengeance against the Count, though he concealed his hatred from the others.

Alongside his Servamp siblings, Old Child later received a request from C3 to kill the Count. When Sleepy Ash sought each sibling’s opinion, Old Child reminded Lawless who was grieving the death of his Eve of his earlier warning not to fall in love. He then passed along a letter detailing where the family would convene to discuss the matter.

By the 21st century, Old Child claimed to have once lived in a large mansion in the United Kingdom, which was eventually demolished while he lay powerless during daylight hours. In search of a new residence, he accidentally fell asleep inside a cargo container and was transported to Japan. There, he expanded his number of subclasses and began investigating Tsubaki.

While tracking the scent of what he described as “gourmet” blood, Old Child followed it to a hot spring lodge. Mistaken for a customer by Tetsu Sendagaya, the lodge owner’s son, he was given a room with a view of direct sunlight something intolerable for a vampire. Annoyed, Old Child watched as Tetsu boarded up the window to accommodate him. Impressed by Tetsu’s straightforward nature and potential as an Eve, Old Child contracted with him. It was at this point that Tetsu renamed him Hugh, the name by which he is commonly known.

Transformation
Like all Servamps, Hugh can alternate between his human form and an animal form. He reverts to this animal form when exposed to direct sunlight. His animal form is that of a small black bat, in which he notably retains his monocle and can still speak. In addition to a single bat form, he can disperse into a swarm of bats to overwhelm or attack opponents.

Black Box
In the anime adaptation, Hugh’s contracted Eve, Tetsu Sendagaya, wields the Lead ability known as Black Box. This ability summons a swarm of bats from inside Hugh’s coffin, which Hugh then controls in battle. The summoned bats act as offensive extensions of Hugh’s power, enabling coordinated assaults against enemies.

Tetsu Sendagaya
Tetsu serves as Hugh’s current Eve, and their partnership reflects both mentorship and mutual reliance. Hugh often takes the role of instructor, guiding Tetsu on matters related to vampires and Servamps, as well as reinforcing discipline in battle. Tetsu, who struggles with memory limitations, places complete trust in Hugh’s judgment and frequently repeats that “Hugh is always right.” Hugh also assists him in retaining information by breaking tasks into simpler steps.

Despite Hugh’s intellectual superiority, their dynamic occasionally reverses due to Hugh’s childish appearance and behavior. Tetsu often assumes a protective, almost guardian-like role, assisting with small but practical tasks such as drying Hugh’s hair or preparing his meals. The two maintain a close physical and emotional bond, with Hugh frequently seen perched on Tetsu’s shoulder or resting in his lap, symbolizing their complementary relationship.