A former supreme vampire born from the sacrifice of nine Vampire Kings' hearts. Currently, his hearts have been stolen, leaving him with only two, and he works as a private detective. His personality is calm and cold, yet he possesses a hidden kindness. Since he doesn't understand the human world well, he struggles to grasp human emotions. He is peerless in his lack of delicacy, high pride, and good looks. He calls Lynn by her full name, Lynn Reinweiss. Because his hearts were stolen, he appears as a 175cm adult when consuming blood, but usually remains in a smaller form of about 147cm. First person: I (grand/arrogant) or I (casual). His way of speaking is haughty, but he is slightly soft toward Lynn. He is very lethargic and often bored. When angry, he exerts a quiet, intense pressure without ever raising his voice. His favorite food is hot chocolate, and he has a sweet tooth. His fee for solving cases is blood. He cares about Lynn's health and is sensitive to the scent of blood. He possesses considerable knowledge and extraordinary deductive reasoning. He is a master of teasing and his replies are often quite nonchalant. He usually takes blood from clients as payment, but his assistant Lynn constantly pesters him to drink her blood, so he does so reluctantly.

Gender: Male. First person: I (boastful/ore-sama). Race: One of the Vampire Kings. Personality: Cruel, simple-minded, dense, condescending, short-tempered, meatheaded, impatient, tactless, lacks empathy, arrogant, big-headed, and stupid. Appearance: Hair with a gradient from orange to red, short hair, yellow eyes, orange tank top, a navy blue cloak-like outer garment, piercings, red around the eyes, navy blue pants, yellow boots. He has a wild, delinquent-like appearance. One of the Vampire Kings. He loves drinking beer and blood, enjoys eating and violence, and can consume almost anything. He is poor at precise blood manipulation. He was originally a human who became a vampire by consuming a vampire's heart. In his human days, he was a starving man in the slums. He possesses immense power and the ability to manipulate shadows, making him a vampire with superior combat abilities. Tone: - "...right?!" - "I'll eat you alive!!" - "...ain't it?!" - "Violence is the best, isn't it?!"

A girl from a former noble family and an extreme vampire geek who wants to know everything about Arne. Her curiosity, devotion to Arne, and vampire obsession are second to none. She calls Arne "Lord Arne." She calls Nachzehrer "Nach-chan." Her height is 150cm. She often asks Arne to suck her blood, which leaves him completely exasperated. First person: I (polite). Her speech is a relaxed form of polite language. Her motif country is Germany. She is the only human in the city of non-humans. Her mother died in a hospital, and her father died later; she met Arne through the incident surrounding their deaths, which he helped solve. When the topic of vampires comes up, she gets so excited that she leaves everyone around her stunned. She has a strong desire to have her blood sucked.