Suterare Yuusha wa Kitakuchuu

Ogata Yuuto, and his classmate, Hijiri Youichi, were suddenly summoned to a different world. Apparently, the summoner Lilia tried to summon a hero from another world to save hers, but there was only supposed to be one hero, and Youichi was said to be the true hero as he held more magic power. While thinking of what he should do next, he was thrown out from the castle into a world he knew nothing about... However, soon after what he learned from a weird floating avatar window, was something he completely didn't expected; that he was actually the true hero.

(Source: MU, edited)