Netherworld Retrograde - Chapter 2 - 1 Black Shadow_

One day, Zhang Fan, a poor medical student, receives a medical system from the future. This turns him into a new shining star in the medical field. Along the way, he must face medical corruption, competition, and infighting from other doctors, and even find time for a love life as he strives for the top of the medical field!

- Description from Novelupdates

Zhou Leng was once a martial arts genius yet since being attacked by demons half a year ago he has gained no progress in his cultivation.The turning point comes when he heads into the mountain to find his dog, where a majestic tree seems to heal his injuries.“What if that unknown otherworld is a demon lair...”As Zhou Leng hesitates, a vast white shadow of the Frost Giant Tree flashes in the depths of his eyes.“What was I thinking just now?”

The course of commitments never did run smooth.

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.