Seikatsu Mahoutsukai no Gekokujou

I'm not "useless!" I'll prove it by conquering dungeons!

One day, magical dungeons suddenly appear in modern Japan, and daily life is completely transofrmed. Gurimu Sakaki was born with a talent for life magic that seems useless for exploring dungeons or defeating monsters. But while exploring a dungeon, he finds a rare item, the "Sage System," which allows me to create new kinds magic…?

(Source: ComicWalker, translated)