Level Down No Wana Kara Hajimaru around Thirty Otoko No Banno Seikatsu (DASH X Bunko) [Light Novel]

[Machine Translation] Allen, who became an adventurer at the age of twelve to support his younger siblings, is an Alaska man who started working as an employee of an adventurer's guild when they became independent. His job, however, is a very menial chore of managing a slime dungeon. Then one day, the dungeon is suddenly altered! In a hidden room discovered during a solo investigation, Allen steps on something that will revolutionize his destiny...? Allen's mood is drastically down because of the "Level Down Trap," but suddenly he has an idea for a big turnaround? ( Can this make me stronger than ever? ) He is a simple guild scullery worker by day, but behind the scenes he is a mysterious and powerful adventurer who destroys powerful enemies one after another...? A simple man in his twenties gets a fresh start! Behold a fun and versatile double life that is both "ordinary" and "extraordinary"!

幼い弟妹たちを養うべく十二歳で冒険者となったアレンは、彼らの独立を機に冒険者ギルドの職員として働き始めたアラサー男。だが仕事はスライムダンジョンの管理という非常に地味な雑用。そんなある日、突然ダンジョンの改変が発生!単独調査で発見した隠し部屋で、アレンは自らの運命を大変革するものを踏む...?『レベルダウンの罠』による弱体化で気分激落ちのアレンだが不意に大逆転のアイデアをひらめく?「これって滅茶苦茶強くなれる?」日頃は地味なギルド雑用職員、裏では強敵を次々に殲滅する謎の最強冒険者へ大変身―?地味なアラサー男のやり直し!『平凡』で『非凡』な楽しい万能二重生活を刮目せよ!!!