Houkago wa, Isekai Kissa de Coffee wo

Yuu found himself in another world, where now he spends his time not adventuring in the town's labyrinth, nor hunting down a demon lord, but running the world's only café. His days pass as he hopes for an upswing in popularity and works towards keeping his... eccentric regulars happy.

One day, a student attending the town's magic academy finds his café when looking for a quiet place to study...

(Source: Novel Updates)