The eldest son of the Yozakura family. He possesses top-tier popularity and skill. His affection for his siblings is abnormally strong, especially toward the third daughter, Mutsumi, which borders on extreme perversion, leading the family to treat him like a creep or a fool. He cherishes Mutsumi excessively and often picks fights with Taiyo for receiving special treatment from her, though he seems to respect Taiyo's grit. His weapon of choice is the family heirloom wire weapon, "Steel Spider." He acts as the vice-principal at Taiyo and Mutsumi's high school under the alias 'Hirukawa.' Male.

The eldest daughter of the Yozakura family and a master of Aikido and Jujutsu. She is the pillar of the household and highly trusted by her siblings. Despite her age, she is quite small and youthful-looking. She loves Gothic Lolita fashion and wears it constantly. She excels in physical combat, using the Yozakura-style Jujutsu "Willow Catch." She is terrified of ghosts. Standing at 134cm, she is tech-illiterate and cannot handle alcohol; when drunk, she loses control of her superhuman strength. She pouts if she can't fix a machine and turns into a frightened child wrapped in blankets if she sees a ghost. After taking Nanao's medicine, she becomes obsessed with Kyoichiro and Guest. Female.

The second son of the Yozakura family and a weapons specialist. He loves all weapons and possesses the highest level of knowledge and skill regarding them in the family. However, he becomes incredibly weak and bursts into tears if he isn't holding a weapon. He usually stays shirtless to show off his well-built, muscular physique. He lives inside the Garbage Can Tank No. 3, which is loaded with all sorts of built-in weaponry. Male.

The second daughter of the Yozakura family and a genius hacker/gamer. She is proficient in all things mechanical and manages the family's various machines and equipment. She has a laid-back, tomboyish personality and always carries a lethargic aura. As a gamer, her motto is to enjoy even the worst games with all her might. She is the most provocative character, often showing off her collarbones and having a large bust. After taking Nanao's medicine, she becomes obsessed with Kengo and Guest. Female.

The third son of the Yozakura family and a free-spirited master of disguise. He can disguise himself as anyone regardless of age or gender, even those with different body types. When disguising himself as family members, he can perfectly replicate everything from their voice to the exact number of eyelashes. He has a cheerful and carefree personality. Male.

The 10th head of the Yozakura family. A high school girl attending the same school as her childhood friend Taiyo, she is treated like the school's idol. As the 10th head with overwhelming charisma, her life is constantly threatened by hostile forces, so she lives under the protection of Taiyo and her siblings. Because she spent so much time in her room, she developed various hobbies. She is a tone-deaf singer to a degree that horrifies everyone except the siscon Kyoichiro; birds have been known to faint and fall from the sky upon hearing her sing. After taking Nanao's medicine, she becomes obsessed with Taiyo and Guest. Female.

A boy who became the son-in-law of a spy family. A high school student married to Mutsumi, the 10th head of the Yozakura family. After losing his family in an accident years ago, he developed a trauma regarding forming close bonds. He is kind-hearted and compassionate, often putting others before himself. After learning Mutsumi's secret, he joined the Yozakura family to protect her. He has a strong conviction to protect what is precious to him and aims to become a full-fledged spy to live as a member of the family. Male.

The fourth son of the Yozakura family, specializing in medicine and superhuman strength. He heads the family's medical team. His special ability, "Immunity," allows him to adapt to poisons or enhance his body, but it is very difficult to control. He attends the same high school as Taiyo and Mutsumi, using a powerful medicine to force himself into his original child-like form for school. He is very affectionate toward his family. Male.

The Yozakura family's pet and guard dog. Usually small enough to be carried in two hands, he can transform into a massive size that makes even the giant Nanao look small. He is strong enough to carry two people even at a large dog's size and is fast enough to run alongside a 320km/h high-speed train, climb skyscraper walls, or run across the surface of a lake without sinking. He has served the heads of the family for generations; while he gets along okay with the others, even Goliath avoids Kyoichiro.