Isekai Quest After School!

Isekai Quest After School! summary:

Tsugami Kazaya is an experienced swordsman who travels to another world and back again on a daily basis while also attending high school! After a certain incident, he ended up instructing a senior student from his high school, the beautiful Mikoto Chihiro, on the basics of adventuring! After that, Chihiro, who was usually cool and difficult to approach, started to show her true bright personality only to Kazaya!? “I did it! I did it, Tsugami-kun! I was able to slay it!” “S-Senpai, don’t you think your personality has changed a little too much!?” The Earth and the other world, a RomCom and an adventure story, the two of them travel constantly between the two!! It’s the start of a new twist on a fantasy after school!!