The MC wasn't an imp, he's a human. That Death March sounds pretty good also though.
It was written in English. I believe it was Lit RPG style. Main character is a human Male. I usually search for Adult themes, smut, but can't remember if this story had any.
I started a story where the MC wakes up and calls down asteroids or nukes or something. He ends up in a town, befriends a female city guard/magic user, ends up fighting a demon that creates an underground dungeon.
I didn't save the story to my reading list, and haven't been able to find it...