Mudou

If you're just following your mother's footsteps, I don't recommend it. Your distorted devotion will lead you to your destruction, Itsuki-chan. It's almost like a curse Mudou (tentative name) is the ex-husband of the late Rena Nakano and the biological father of the Nakano Quintuplets whom he finally meets in the upcoming movie of the 24-episode anime.

Appearance
Mudou appears to be an old man; lacking hair on his head and his grown out, white-colored beard being his most apparent feature.

Personality
As the newfound father of the quintuplets, much of his identity has yet to be revealed, but he seems to have ever regretted his decision of leaving his daughters too many hardships. Stating that he wants to "atone" for his sins.

He holds some animosity towards Maruo Nakano because of allowing his quintuplet daughters to follow the same misguided path as did his late wife.