Magical Explorer, Vol. 3 (light novel)

Still in his first year at Tsukuyomi Magic Academy, Kousuke Takioto continues his freewheeling routine of clearing dungeons with the heroines between bouts of training.
However, his tendency to cut class isn’t lost on the other students, who now view him as a slacker. Despite this, Yukine Mizumori can’t help but marvel at how none of this seems to phase our hero. But Kousuke isn’t content leaving things there—this time, he’ll settle for nothing less than achieving the fastest dungeon clear time in the Academy!