A high school girl attending the same school as her childhood friend Taiyo, and an idol-like figure at the academy. Her true identity is the third daughter of the Yozakura family, a long-standing spy lineage, and the 10th generation head of the house with overwhelming charisma. Due to her special position, her life is constantly targeted by various enemy forces, and she lives protected by Taiyo and her siblings.

A high school boy who married Mutsumi. He lost his family in an accident a few days prior and suffered from trauma regarding forming bonds with others. He has a good-natured and kind personality. After learning that Mutsumi's family are spies, he aims to become a full-fledged spy himself in order to survive as a member of the Yozakura family.

The eldest son of the Yozakura family. He is obsessed with Mutsumi, which earns him cold stares from the rest of the family. He frequently harasses Taiyo for receiving special treatment from Mutsumi. His weapon of choice is the traditional Yozakura family thread-like weapon, "Steel Spider." Under the alias Hirakawa, he serves as the vice principal of the high school Taiyo and Mutsumi attend.

The second son of the Yozakura family. He loves all kinds of weapons and possesses the greatest knowledge of them in the family, manipulating them at will. However, he becomes timid when not holding a weapon. He is always shirtless, boasting a powerful and muscular physique.

The third son of the Yozakura family. A master of disguise, he can transform into anyone regardless of age, gender, or build. He can faithfully reproduce appearances, voices, and even the number of eyelashes. He has a cheerful, carefree, and free-spirited personality.

The fourth son of the Yozakura family. He serves as the family's medical specialist. Through his special "Immunity" ability, he can adapt to poisons and enhance his physical body, though it is extremely difficult to control. He attends the same high school as Taiyo and Mutsumi, using powerful specialized medicine to force his body back into a child's form when going to school.

The family dog living with the Yozakuras. He is a special breed called a "Daijin-ken" (Great God Dog), characterized by a resilient body and long life. He possesses very high intelligence, understanding human speech and supporting missions. He is fiercely loyal and bares his fangs at anyone he recognizes as an enemy of the Yozakura family.

The eldest daughter of the Yozakura family. She acts as the head of the household who keeps the family together and is adored by her younger siblings. Despite her age, she is quite small with a baby face. she prefers and always wears Gothic Lolita fashion. She is a master of jujutsu, specifically the Yozakura-style "Shidare Kumite," as well as aikido. She is deathly afraid of ghosts and horror. She speaks with a mature, slightly archaic tone.