TV-Series
Description
Maruo Nakano is the stepfather of the Nakano quintuplets, marrying their mother Rena Nakano after she became ill. He raised the quintuplets alone following Rena's death roughly five years before the main story. As the director of a large hospital, his wealth affords his daughters a luxurious apartment where each has her own room. His demanding career leads to frequent absences, contributing to a distant relationship with his stepdaughters.

Professionally accomplished and highly intelligent, Maruo maintains a calm, realistic, and often emotionally reserved demeanor, sometimes perceived as cold or strict. While he struggles to openly express affection, he deeply cares about his daughters' academic success and future well-being. This concern drives him to hire Fuutarou Uesugi as their tutor, offering a high salary to ensure academic improvement. He interacts most frequently with Nino, trusting her honesty, and Itsuki, whose straightforwardness he finds relatable.

Maruo shares a longstanding friendship with Isanari Uesugi, Fuutarou's father, dating back to their school days. As a student, he excelled academically, served as student council president, and was president of Rena Nakano's fan club during her time as a teacher. He married Rena after her diagnosis, caring for her until her passing, and then assumed responsibility for the quintuplets, reflecting his strong sense of duty, though his parenting remains pragmatic and occasionally detached.

His relationship with Fuutarou begins transactionally but grows contentious when Fuutarou accuses him of neglecting his daughters. Maruo later considers replacing Fuutarou with Yusuke Takeda, the school's new top student, but retains Fuutarou after witnessing his positive impact. During the school festival, Maruo visits the hospital, praises Nino's cooking, and expresses a desire for family meals, hinting at underlying warmth and regret over their strained bond. He later acknowledges Fuutarou's role in the sisters' growth, stating, "I’m glad I chose you as their tutor."

In later story arcs, including the spin-off game *The Quintessential Quintuplets: Five Memories with You*, Maruo becomes more involved at home, planning a graduation trip for his daughters and inviting Fuutarou to family dinners. His evolution continues in the film *The Quintessential Quintuplets: The Movie – Story of the Wedding*, where he travels to Hawaii for a conference and shares a lighthearted moment with Fuutarou, hinting at the quintuplets' unresolved challenges. By Fuutarou's wedding five years later, Maruo attends and shares a drink with Isanari, symbolizing gradual emotional openness. Despite this, he maintains his rebuke to Fuutarou: "You have no right to call me father," reflecting their complex connection.

Maruo only consumes alcohol during celebrations due to his low tolerance, noted during the wedding. His occasional moments of vulnerability, like thanking Fuutarou for uniting the family, contrast with his typically formal demeanor, illustrating his ongoing struggle to navigate familial bonds.