My Childhood Friend and the Cuckold Dungeon

A young man, Kai, runs away from a country town, dreaming of becoming an adventurer.
A young girl named Eri follows in his footsteps.

Kai is intimidated by his meddlesome childhood friend,
Kai takes on the challenge of dungeons as an adventurer.
However, he has no idea what Eri is doing behind the scenes of his adventures. ……​