Count D is the enigmatic proprietor of a mysterious pet shop located in Chinatown. He is a slender, androgynous figure with pale skin, long dark hair, and mismatched eyes; one is purple and the other is gold. He typically wears ornate, colorful Chinese clothing and has sharp, dark nails. Although customers and others refer to him as Count D, he insists this is not his true name, claiming the title belongs to his grandfather who is the shop's real owner but is currently traveling abroad.

His background is steeped in tragedy. D belongs to an ancient, non-human lineage from a lost civilization in the Kunlun mountains. This race lived in harmony with animals and served as messengers and priests in the imperial court. When a prince's marriage proposal was rejected by a priestess, he ordered a genocide of their people, leaving only one survivor who swore vengeance against humanity. The family has perpetuated itself through a form of cloning, with each generation looking nearly identical. D himself was raised by his grandfather and has a strained relationship with his father.

D’s personality is a study in contrasts. On the surface, he is calm, gentle, and impeccably hospitable to his customers, frequently serving them tea. He possesses a particular fondness for sweets and confectionery, a weakness that others, particularly a detective named Leon Orcot, often exploit. Beneath this placid exterior lies a deep-seated disdain for humanity, rooted in the historical atrocities committed against his people and a more profound grief over the suffering and death humans inflict upon animals. He believes in an extreme form of justice, where the punishment for harming animals is often death, and he shows little compassion for customers who break the terms of his contracts, viewing their gruesome fates as the consequences of their own failings.

His primary role in the narrative is as the catalyst for judgment. He does not simply sell pets; he offers love, dreams, and hope in the form of seemingly magical or mythical creatures that often take the shape of a customer’s lost loved one. Each sale is bound by a three-clause contract. When a customer inevitably breaks one of the rules, the pet enacts a terrible revenge, leading to the customer’s demise through supernatural means. D sees himself as an impartial executor of this justice, a role that stems from his family’s centuries-old vow of revenge.

Key relationships are central to his development. His most significant connection is with Detective Leon Orcot, a homicide investigator who suspects D of being involved in the strange deaths linked to the shop. Initially antagonistic, their relationship evolves into a peculiar friendship, with D providing Leon with cryptic information in exchange for expensive sweets. Another pivotal relationship forms with Leon’s younger brother, Chris. Despite D’s stated dislike for human children, he becomes a caring and protective guardian for the traumatized boy, which begins to soften his rigid views on humanity and challenges his inherited mission of revenge. This development creates an internal conflict between his duty to his family and his growing, genuine affection for specific humans.

Notable abilities stemming from his non-human nature include the power to communicate with all forms of life, from mundane animals to mythical beasts. He has a form of mind manipulation, often enhanced by special incense in his shop, that can alter human perception or memories, particularly with his golden eye. His blood possesses the remarkable property of life itself; any blood he sheds can spontaneously generate flora or fauna, from flowers to great beasts like condors and tigers. He also possesses accelerated healing, recovering quickly from severe wounds, and is fluent in every human and non-human language.