Nao Fueki

Nao Fueki is a third-year student at Kiyose Academy. He is a rather reserved individual, and comes off as mean to others. He is also quite sharp, as he is very perspective and catches onto things easily. Nao leads a secret double-life as a vigilante, however he only does so to make sure his younger brother Junichi Fueki stays out of trouble. 

It was just Nao and Junichi as vigilantes for about six months, but when Junichi was in danger, a young lady came to his rescue before Nao could. This stranger revealed herself as Maile Sano, a transfer student from Matsugaya Academy. Her circumstances, as Nao found them, were rather complicated, and he found her suspicious. Junichi, however, was fascinated by Maile and even invited her to join their group. Nao objected immediately to this, but Maile ended up joining. 

Things for the vigilantes changed shortly after Maile joined, as another young lady, Hoshi Akari, ended up joining them. Nao was rather cold to both Maile and Hoshi, and he has butted heads with Maile on multiple occasions. The four of them found themselves caught up in a bigger mystery revolving around their beloved city of Shibuya. As they worked through this together, Nao warmed up to Maile and Hoshi, and soon enough he considered the vigilantes his best friends, willing to protect them at all costs.