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

Suddenly, magic and dungeons appear in modern Japan, and life has changed completely. I, Gurimu Sakaki, am born with a talent for life magic that cannot be used for exploring dungeons or defeating demons. I was born with a talent for life magic, but while exploring dungeons, I got my hands on a rare item, the "Sage System," which allows me to create new magic...?

(Source: Kadokawa, translated)