Family Members[]
The Nakano Quintuplets[]
While Maruo is not the quintuplets' biological father, he genuinely cares for his stepdaughters, which is shown in his decision to hire Fuutarou Uesugi, the best student in class, as his stepdaughters' tutor, despite disliking him. He also doesn't force his opinions and decisions on the quintuplets. When the quintuplets decide to move out from their residence to live independently, Maruo becomes displeased. Even so, he still considers their thoughts and allows them to do so.
Rena Nakano[]
Maruo was once a student of Rena, and according to Isanari Uesugi, he was the president of her fan club in junior high school, implying that he harbored strong romantic feelings for her.
Many years later, when Rena fell ill and had to be hospitalized, Maruo became her doctor and he would often visit her, as noted by the Nakano quintuplets. They married sometime before her death, and he would continue looking after her daughters in her memory.
Other Characters[]
Ebata[]
Ebata is the Papa Nakano's secretary and occasionally driver. Due to Papa Nakano's lack of time and attention towards his stepdaughters, Ebata is assigned to take care of the quintuplets.
Isanari Uesugi[]
Isanari has a relationship with Papa Nakano prior to the beginning of the series. Through Isanari, Fuutarou was able to land the job as the quintuplets' private tutor. It is implied the two have known each other for some time, with Isanari being aware that Maruo does not drink.
It was later revealed that Isanari and Maruo were once classmates.
Fuutarou Uesugi[]
Despite choosing Fuutarou as the quintuplets' private tutor, Papa Nakano bears a certain hatred toward him. This is implied to have partly came from Fuutarou telling him off following the fight between Nino Nakano and Itsuki Nakano. He denies Fuutarou and objects him marrying one of his daughters.
Despite his treatment and attempts to rid his daughters of Fuutarou, he does admit he is impressed by Fuutarou's resolve and acknowledges his academic performance. He positively notes Fuutaoru's change in attitude towards being the sisters' tutor as opposed to Fuutarou's initial reluctance.
During the wedding between Fuutarou and his stepdaughter, Papa Nakano refuses to show up with Fuutarou until Isanari reprimands him.