OVA
Description
Kai Sagano, born March 17th in Osaka, is the legitimate son of yakuza boss Takeshi Sagano. He shares his father with his older half-brother, Kei Enjouji; both their mothers are deceased. Raised within the yakuza world and addressed as "Bon" by associates, Kai holds no operational role in the organization.

His privileged yet neglectful childhood proved emotionally turbulent. A pivotal betrayal occurred at his mother's funeral when his father revealed Kei's existence, igniting Kai's lasting resentment. He blames Kei for family discord and personal hardships, including Ranmaru Samejima's accident. His relationship with his father remains strained, marked by confrontations over the father's prioritization of yakuza duties over parenting, leading Kai to dismiss later reconciliation attempts with skepticism.

Kai develops an intense fixation on Ranmaru Samejima, evolving from idolizing the kendo prodigy to romantic infatuation. This fuels his rivalry with Kei, whom he perceives as obstructing his connection to Ranmaru. He rescues Ranmaru from a drugging and assault attempt by a professor, but subsequently takes advantage of Ranmaru's compromised state. Despite this transgression, neither Ranmaru nor Kei holds lasting resentment. His pursuit of Ranmaru results in temporary disownment by his father, who disapproves of same-sex relationships. Though his feelings for Ranmaru persist unrequited, he redirects his focus towards kendo challenges against him.

His most complex relationship is with Masanori Araki, his father's second-in-command and designated successor. Araki, his protector and caretaker since infancy, fostered a bond that gradually shifted from familial to romantic. Their dynamic is complicated by power imbalances inherent in Araki's role as a subordinate and Kai's status as the boss's son. Kai struggles to articulate his feelings, initially denying broader same-sex attraction by insisting his love for Ranmaru was unique. He later confronts his father about his sexuality and reacts with confusion to Araki's implied romantic interest. A pivotal moment occurs when Araki, impaired by painkillers after sustaining a facial scar protecting Kai, initiates intimacy; Kai reciprocates, but Araki halts the encounter upon regaining clarity.

Exhibiting early impulsiveness and entitlement, Kai experiences gradual maturation. He channels his competitive drive into kendo and reveals ambitions to reform his family's yakuza operations into a legitimate business. His relationship with Araki progresses towards mutual acknowledgment of romantic feelings, though its resolution remains open-ended. Persistent themes involve his navigation of familial loyalty, acceptance of his identity, and reconciliation of his privileged yet fractured upbringing.