Solo Leveling: vol. 4

When Jinwoo sets about mentoring one of Jinho's recruits- who also happens to be his sister's good friend-a White Tiger Guild training operation seems like the perfect opportunity to show her what being a hunter really entails. But the moment he and Songyi enter the gate, Jinwoo realizes something is wrong. With a flash of red, the exit vanishes, stranding them and the White Tiger trainees in a frozen forest for what could be weeks-or until someone can defeat the dungeon's formidable boss...

Translated from the original Korean (which makes this manhwa, rather than manga!)