Kaban no Yuusha no Isekai Nonbiri Tabi ~Jitsuwa "Kaban" wa nani demo Kyuushuu Dekirushi, Nihon kara nandemo Toriyose ga Dekiru Cheat bukideshita~

Keisuke Sakuhira, a boy about to become a high school student in spring, is suddenly summoned to another world one day and told to defeat the Demon King as a hero. However, the [Holy Weapon] divinely bestowed upon him is just an ordinary school bag...!? Immediately after, Keisuke is branded as a failure of a hero and abandoned in a deadly dungeon swarming with powerful monsters...!! Just when he thought he was doomed to die—his supposedly useless bag unleashes an astonishing power!?? The curtain rises on a "ridiculous great adventure" of a hero leisurely traveling another world with just one bag!