Kaji is in the same grade as Ayu and Nina, and is also the school idol. He is considered cool and always has a nice smile. All his fans are constantly giving him presents, and he even has admirers from the 3rd grade. However, this is only his outer mask. Kaji is in reality a normal guy who hates being given presents by people he doesn't know. But he is working hard on his "nice person" persona because the girl he likes, Ayu, once told him that's the way she liked him. He becomes closer to Nina after she discovers his deception. He is an introverted person, and doesn't like giving away his real feelings or thoughts. Kaji belongs to the school's baseball club. His best friend is Tsujiai.
Tsujiai is a classmate of Kaji, Ayu and Nina. He is the head of the male tennis club and is a slightly extravagant person. Ayu seems to hate him because at the start, he always managed to destroy her chances with Kaji one way or another. Tsujiai introduces Nina to Doraemon (which she loves). His best friend is Kaji and he likes Nina which is shown more in the manga than in the anime. He has a cat name Shinnosuke and is the third person to know that Nina was a magic girl because he saw that Rio the cat transforms into a human.
One of Makoto's work colleagues. Not married. Envies Makoto because of the beautiful wife he has. As well as Okahama sometimes acts like a pervert. Is not really attentive to his sex partners (which is discovered during the girls' talk about the worst types of men).
One of Makoto's work colleagues. Not married. Has many fantasies about women and often says vulgar things making Makoto blush. Okahama himself thought he was good at sex until girl colleagues started to discuss the types of men they hated most. Then it revealed that he had a lot of problems, f.e. thought only about himself.
Makoto's father. A 52-year-old company officer. He is overly sensitive about his sex life, and far too protective of his youngest child, Jun. (source: http://en.wikipedia.org/wiki/Futari_Ecchi)
Makoto's elder brother. A 29-year-old lawyer. He is very nosy and frequently pesters Makoto about his sex life and fancies himself as Makoto's tutor on the topic of pleasuring women. In order to appease his own sex drive, he frequently visits brothels. Is used to speak in an extremely loud voice which (along with the topic Akira usually covers) makes everyone embarrassed.