MTL - My Runes Can Be Upgraded - Chapter 8 boar king

The world that nurtured the civilization which reached the pinnacle of magic was on the verge of destruction.
The last survivor transmigrated to the past, when the magic civilization started growing, as countless mages were still fumbling their ways through the thorny paths of magic knowledge.
He, who came from the end of the magic era, aim to reach the pinnacle of magic.

- Description from Novelupdates

Waking up, Kim Hajin finds himself in a familiar world but an unfamiliar body.

In a world ravaged by demonic hordes and warring clans, where does humanity end and monstrosity begin?After being murdered in a back alley, Lidien awakens in the body of a demonic prince... a youth bound by tragedy and trapped in a brutal clan.To survive, he must master the strange abilities granted by a crimson shard fused to his soul: hearing the whispers of the dead, reading memories imprinted on flesh, and inciting his own blood to rage.But Lidien soon learns his rebirth was no accident. He is a vessel for a dormant god, and his very existence is entangled in a cosmic struggle far beyond the savage politics of his new family.To protect those he cares for and control his own destiny, he must unravel the mysteries of death, power, and the abyss within himself.This is the legend of the Prince of Death.----------This novel includes politics, kingdom building, psychological elements, and is not solely about powerups.

One day, Luo Jian woke up from his sleep and found himself in a locked chamber where the door and window were all sealed. A note with a few lines written on it was tacked to the wall: “Escape from this room within an hour, otherwise, you will die.”

There is a sequel called Reincarnation Night (轮回之夜) that takes place in the same universe but has different main characters

- Description from Novelupdates