Dungeon Haishin wo Kiriwasureta Yuumei Haishinsha wo Tasuketara, Densetsu no Tansakusha toshite Bazuri Hajimeta: Inkya no Ore, Nazo Skill dato Omotteita "Rule Mushi" de Ukkari Musou

Tsukushi Kirishima is a born loser, a second year high school student who is mocked even by his underclassmen. He has been granted a mystery skill called "Ignore Rules," but he doesn't know how to use it, so he struggles in obscurity both as a student and an explorer. One day in a dungeon, he encounters the famous streamer Miru Ayatsuki. Miru's goal is to film the "emergency monster" that has suddenly appeared in the dungeon, but its strength poses an uphill battle and he finds herself in mortal danger! The same moment Tsukushi intervenes and comes to her rescue, the mystery skill "Ignore Rules" activates...

(Source: Futabasha, translated)