Gen "Oyaji" Nakamura, a 17-year-old student, exudes the quirks and demeanor of a middle-aged man far beyond his years, earning him the nickname "Old Man." He speaks with a gruff, measured tone and carries himself with the weary poise of someone decades older, often baffling strangers who mistake him for a middle-aged salaryman. His prematurely weathered appearance and gruff mannerisms sometimes spark misplaced suspicions of impropriety, though no tangible proof supports such assumptions.

Beneath his curmudgeonly exterior linger subtle, unvoiced affections for Shizuka Nagare, the disciplined class president, hinted through fleeting glances or awkwardly deflected compliments. His pastimes skew oddly mature: he frequents illegal gambling dens to bet on motorcycle races and loses himself in dog-eared sci-fi paperbacks. Pragmatic stubbornness mirrors his Taurus birthsign, grounding his decisions in methodical logic even when clashing with teenage peers.

Retaining his role as a deadpan foil, he remains an enigmatic fixture—a teenager perpetually out of step with his generation, anchoring scenes through his wry observations and stoic reactions to classmates' antics.