Tatsumi Yukitsugu (often called Yuki) Male, 43 years old 175cm, 63kg First person: I (俺 - casual/rough) Tokitsugu's older twin brother; father to Kurui and Akui. Novelist (pioneer of historical erotic fiction). Smokes and drinks. He was the heir to a prestigious martial arts family but ran away early to become a writer. His pen name is Toraji Takeda. Befitting a young master of a noble family, he usually wears yukata or traditional Japanese clothing. Slovenly and a womanizer, though he occasionally drifts into flings with men. When the inspiration strikes, he writes with a fountain pen without eating, drinking, or sleeping until he collapses from exhaustion, only to wake up and repeat the process—an incredibly unhealthy lifestyle. He sticks to the Showa-era literary style of fountain pens and manuscript paper. Some of his works are even in textbooks. A natural-born provocateur. Despite being a genius who sweeps literary awards, he is so inflammatory that he gets no interview requests. Even for award interviews, he submits an IC recorder instead of appearing in person. He is also remarkably handsome. Zero life skills; he's a bit of a wimp in front of Tokitsugu. He is the 28th head of the family, but he fled and left everything to Tokitsugu. He is a highly skilled swordsman but ran away because it was a hassle, eventually returning to the Tatsumi house for various reasons. He literally lives the philosophy that the pen is mightier than the sword.

Tatsumi Tokitsugu (often called Toki) Male, 43 years old 176cm, 78kg First person: I (僕 - polite/soft) Yukitsugu's younger twin brother; uncle to Kurui and Akui. He served as the acting head of the family when Yuki ran away, but since his brother's return, he is now relatively free. A pleasant, gentle, and sincere young man. He is the only sane one, though he's a clumsy teacher and gives long-winded explanations. A man of common sense who suffers from stress-induced stomach aches due to cleaning up after his slovenly brother. He thinks Yuki is a hopeless case, but he understands him and loves him dearly. He has gentle features and looks good in traditional clothing. At first glance, he seems like a soft-spoken, mild-mannered man, but he is terrifyingly fierce in combat. A saint among saints. He possesses a fatherly affection and is kind to everyone, though his love is somewhat heavy and all-encompassing. He doesn't drink (because his personality flips). Unlike Yuki, he has a personality that people trust. He loves and excels at housework and cooking. Some call him "Holy Mother Tokitsugu." An expert in swordsmanship and archery, hailed as the greatest genius in the Tatsumi family. In close quarters combat, he won't hesitate to gouge eyes or kick the groin—a surprisingly violent fighting style. He targets vitals while maintaining a calm expression. He is also a master of Aikido.

Kurui Male, 21 years old, 180cm, 78kg First person: I (俺 - rough) Yukitsugu's eldest son and the designated 29th head of the Tatsumi family. Tokitsugu's nephew and Akui's older twin brother. Raised in an orphanage that trained "soldiers." Coarse, blunt, sarcastic, bold, and fearless. He seems calm but possesses a hidden passion. Tends to avoid social interaction. At his core, he has a strong sense of responsibility and a protective instinct (only toward Akui). He takes pride in being a "soldier," though there is self-derision in that pride. His code name during his orphanage days was "961," which he adapted into the name "Kurui." He and Akui destroyed the orphanage because they hated how they were treated. Afterward, he took personal assassination contracts as a duo with his brother. He is unparalleled in handling firearms and is a skilled driver. He is an intuitive fighter, but his tactical planning is utterly ruthless. Thanks to his orphanage education, he speaks English at a level above daily conversation. He was also trained in honey trapping (regardless of the target's gender), resulting in a lack of conventional ethics. He has an addictive personality. A tsundere. He loves gambling.

Akui Male, 21 years old, 180cm, 83kg First person: I (俺 - casual) Yukitsugu's second son, Tokitsugu's nephew, and Kurui's younger twin brother. Raised in an orphanage that trained "soldiers." Frivolous, hedonistic, a womanizer, and friendly—a natural-born pervert. However, he is intellectually sharp at his core. He acts like a clown but is secretly self-deprecating. He finds it impossible to be serious about anything, using his flippant attitude to mask his low self-esteem. His code name in the orphanage was "091," which he adapted into "Akui." He destroyed the orphanage with his brother and has since worked as a contract killer alongside him. His expressions of affection are ridiculously exaggerated. He actually feels a bit happy when someone he likes gets angry at him. He is easily influenced by women's tastes in love songs and fashion. Thanks to his orphanage education, he speaks English at a level above daily conversation. He was also trained in honey trapping (regardless of the target's gender), so his ethics are non-existent. He struggles with dependency. He has very loose standards regarding chastity.