Hiroki Kamijou embodies a man of contrasts, his tsundere nature masking vulnerability beneath a razor-edged facade. As a professor of classical Japanese literature, students dub him “Demon Kamijou” for his habit of hurling objects at inattentive pupils and enforcing draconian attendance rules. This relentless academic rigor stems from a youth fueled by grueling extracurricular regimens, forging an obsession with excellence and visceral dread of failure.

Emotionally guarded, Hiroki’s romantic hesitations originate in childhood—a misguided scheme to win over friend Akihiko Usami by substituting himself as the object of Akihiko’s own unrequited longing. Years later, brash younger man Nowaki Kusama disrupts his solitude after discovering Hiroki in a moment of raw exposure. Though resistant, Hiroki begrudgingly lowers his guard, only to face a six-year rupture when Nowaki departs for overseas study without contact. Climbing academic ranks amid hollow success, Hiroki clings to a trinket from Nowaki’s travels as a fragile lifeline.

Their reunion ignites volatile clashes between Hiroki’s jealousy and Nowaki’s steadfast devotion. Tensions peak when Nowaki accuses him of an affair with colleague Yoh Miyagi—a confrontation that forces Hiroki to acknowledge his desperate need for Nowaki. Reconciliation cements their evolution: Nowaki secures exclusive rights to the affectionate nickname “Hiro-san,” while Hiroki tentatively embraces vulnerability.

Hiroki’s combative camaraderie with Miyagi oscillates between academic rivalry and reluctant mutual admiration, his role as Miyagi’s university counterpart underscoring his scholarly prowess despite personal tumult. Born into privilege yet driven by self-flagellating perfectionism, Hiroki’s competitive streak reflects exacting parental expectations. Fleeting returns to a secret childhood forest refuge—where he first connected with Akihiko—hint at his buried yearning for emotional anchorage.

Through fraught stumbles, Hiroki’s relationship with Nowaki gradually tempers his brittle defenses, replacing isolation with imperfect partnership. His journey charts a transformation from solitary scholar to a man learning to balance intellectual rigor with the messy grace of interdependence, one fragile truce at a time.