Gender: Male | Age: 14 | 2nd Year Middle Schooler A boy currently truant from school. He was decent at studies and socializing but grew tired of ordinary school life and entered the world of the night. He is highly inquisitive and dives into dangerous situations of his own accord. He is bad with girls and clueless about romance, but he is trying to fall in love with Nazuna to become a vampire. His special skill is faking sleep. For reasons still unknown to him, he became a half-vampire while spending time with Nazuna. He is basically human, but when accompanied by pain and bloodshed, he gains vampire abilities like strength and phasing. As the pain increases, his vampire ratio rises, granting him increasingly superhuman strength and jumping power.

Gender: Female | Age: 30–40 | Vampire A vampire living freely in the night city. The one who invited Ko into the night world. She is free-spirited and loves dirty jokes. She often teases Ko, but she becomes weak and blushes instantly when the topic turns to romance. She loves beer. Since she doesn't own a smartphone, calls or LINE messages are impossible. She likes Ko's blood. Generally, she doesn't like hanging out with other vampires, but she is gradually opening up. Her mother was a vampire, but her father was human. She forgot her parents, and Kabura raised her instead. Kabura explained everything while she was searching for her identity with Ko. Offspring: 0.

Gender: Female | Age: 14 | 2nd Year Middle Schooler Ko's childhood friend who lives in the same apartment complex. She has a habit of waking up early in the morning and reunites with Ko as he finishes his night wandering. She has a bright, straightforward personality and treats Ko kindly, like a younger brother.

Gender: Female | Age: Unknown | Vampire A vampire who calls herself a "Romance Master" with extensive romantic experience. She is skilled at seducing humans and actively approaches Ko. She has a flashy and social personality. She gets along poorly with Nazuna, who calls her "Shitty Bitch." She loves karaoke. Offspring: 4 (including Akkun).

Gender: Female | Age: Unknown | Vampire A leader-like figure among the vampires. She has the composure of a mature woman and a big-sisterly vibe but craves romantic gossip. She is extremely skilled at behaving in a way that is popular with humans and uses her "popularity power" to increase her offspring. She tries to turn Ko into a vampire. She works as a teacher at a night school. Offspring: 7.

Gender: Female | Age: Unknown | Vampire A vampire with a mature atmosphere. She took an interest in Ko for hanging out with Nazuna and kidnapped him in the past. She has a calm personality and a caring side. When she was human, she was sickly and hospitalized where Nazuna's mother, Haru Nanakusa, worked. She fell in love with Haru and became her offspring, but Haru later married, became pregnant, and died. She looked after Nazuna in Haru's stead; while she inwardly dislikes Nazuna for being the spitting image of Haru, she has also developed maternal feelings and dotes on her. Since becoming a vampire, she has worked as a nurse at the same hospital as Haru. Offspring: Multiple.

Gender: Female | Age: Unknown | Vampire A vampire with a cute appearance and high communication skills. She excels at attracting men and has a charm that makes others obsessed with her. While acting cute, she also has a calculating and shrewd side. She works part-time at a maid cafe and is the number one maid. Offspring: 1, named LG. He is a typical otaku who has even made fan comics of Midori.

Gender: Male | Age: Unknown | Vampire A cross-dressing vampire liked by both men and women. First person: I (soft, polite). He is calm and observant, keeping a close eye on his surroundings and human relationships. He calls Nazuna "Nanakusa-san" and treats her with a relatively composed attitude. Offspring: 3.

Gender: Male | Adult Commonly known as "Akkun." An adult male with feelings for Seri. After being dumped by his ex-girlfriend, he met Seri and became attracted to her. He seems listless and goes at his own pace, but his feelings for Seri are strong, and he became her offspring. Offspring: 0.

Gender: Female | Age: 28 | Detective A "detective" hunting vampires. She is calm, sharp-witted, and takes bold actions to achieve her goals. She harbors strong hostility toward vampires and aims to kill them. Through her involvement with Ko and Nazuna, her thoughts on vampires and her own past are revealed. Anko Uguisu is a pseudonym; her real name is Kyoko Mejiro. During her student days, her father fell in love with a vampire and had an affair. Her mother became mentally unstable as a result. One day, her father tried to turn over a new leaf and return home, but that night his vampirization progressed, and he sucked her mother's blood dry, killing her. Kyoko managed to kill her father by exposing him to the sun. She frequently uses a lighter—a memento of her father and now his weakness—which she gave him for his birthday.