Horinouchi Seiji

Seiji is a second-year student and Ichio's friend and classmate of Chiharu and Yumi. He is one of the only ones to hang out with Ichio before he was contacted by Tomoko-senpai and it was while hanging out with him in the ramen restaurants that he met Ayano-neesan. It was from that moment that he realized that beings resembling women existed on Earth and that Ayano was one of them.

When Ichio joined the volunteer group, Seiji decided to come and help them because "two men are better than one".

There's been a rumor going around for some time that he would go out with Ayano, which is completely false and impossible.