Maruo Nakano

Uesugi-kun, you've really done it this time. However, I will not hand my daughters over to the likes of you. Maruo Nakano (マルオ) is the step-father of the Nakano Quintuplets and husband of the late Rena Nakano. He runs a large hospital and he is also a doctor. Although he was introduced as an antagonistic character, later in the manga he has shown to be a caring father who only wants what is best for his quintuplet daughters.

His role in the movie remains to be seen.

Personality
Nino Nakano remarks that Maruo always does the thing he deems as correct. He believes in results, which is shown in his decision to hire Fuutarou Uesugi (the #1 student in the class) and his condition that Fuutarou be fired if his daughters' scores are not satisfactory. This also comes into play into rehiring Fuutarou when he scores third in the country for the national mock exam, and is implied to have been able to score higher had he been in a proper condition to do so.

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.

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.

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.

Season One

 * What's Been Built Up (debut; face unseen)

Season Two

 * Good Work Today (full physical debut)
 * The Last Exam
 * Begin the Offensive
 * Scrambled Eggs
 * Sisters War, Part 2 (photograph)
 * The Movie (final appearance)

Season One

 * "You must be Ueusegi. Thank you for looking after my daughters.'"
 * "I don't remember letting you call me Pops."
 * "I'm sorry I haven't been able to make an appearance at home. But I trust that torturing job has gone well thus far?"
 * "Well, that's a relief. I hear the midterms are just around the corner. So I'm glad you;re making progress."
 * "Uesugi, I except great things from you."

Season Two

 * "Ebata, it's such a joyous occasion for all of my daughters' to clear their exams. I wonder if I'm smiling? I see. As their father, that's a given."
 * "Why are you dressed like that?"
 * "It seems that my responsibilities as a parent include listening to my children's selfish wants"
 * "This is your last chance."
 * "Yes, a family vacation. Nothing good ever comes when traveling."