The Strongest Assassin Levels Up in Another World

It was supposed to be a graduation trip, but the bus he boarded was actually headed for the Underworld—where you can’t return to reality unless you keep leveling up and clearing each stage! Every time the bus stops, the passengers are thrown into a mysterious new world: a Chinese-style garden, a city full of statues, dense jungles… Behind each strange landscape lurk countless dangers.
On the surface, he’s just a goofy college student, but in truth, he is Nanase Saku, the No.1 hitman of the dark web.
This was no ordinary graduation trip…

Official Translations:
Japanese