Kujibiki Tokushou: Musou Hāremu ken - Chapter 2

Childhood sweethearts.
The most popular person in school is my childhood sweetheart.

- Description from Novelupdates

Sometimes dying isn’t even the worst part of your dayMark has been reincarnated into a dead town in a bog, one that has been recently destroyed and occupied by ravenous undead. They disappear every day and return again at night, mindless and hungry, hunting for any survivors. He’ll need to use cunning and subterfuge to avoid them, because since he was transported into the body of a child, he can’t level up. At least not yet.Bog Standard. It means “totally normal”, right? But for the small towns found in these bogs, there's no quick rescue and not much trade. Everything has to be made to last. To them, it means “excellent quality”. Mark will have to prove he's Bog Standard if he hopes to survive.This is an Isekai of excellent quality. It’s a progression fantasy set in a LitRPG world, rags to riches with an eventual OP main character. The pacing is slow-burn, incremental progression, sometimes slice-of-life, punctuated by moments of intense violence and possibly traumatic content.

I, a mere con artist, was unjustly imprisoned in Tantalus, the Abyssal Prison meant for the most nefarious of criminals, where I met a regressor.

But when I used my ability to read her mind, I found out that I was fated to die in a year…

and that the world would end 10 years later.