This is a story about Suimei Yakagi, the protagonist from The Other World’s Magic is too far Behind!, during his time on Earth. The magic he uses here is a bit different from the main story, but please enjoy it as a modern version specification.
Isekai Mahou wa Okureteru! Gaiden
The Other World’s Magic is too far Behind! Side Story
Raw Source: https://ncode.syosetu.com/n0506cw/
Author: Gamei Hitsuji
Translator: Gandire Alea