Failure frame : I became the strongest and annihilated everything with low-level spells. Novel 1

Abruptly catapulted into a fantasy world, Mimori Touka and his classmates have been summoned by the world's resident Goddess to serve as heroes. Luckily, most of the students display amazing skills upon arrival--except for Mimori, whose abilities bottom out at a measly E-rank. With no further use for him, the Goddess banishes Mimori to a dungeon from which no one has ever returned alive. Yet, as it turns out, Mimori's skills aren't so much worthl...