The Exorcist - Chapter 9Book 2: : Contractor

Qingyun was probably the only villain who suffered this much.

For hundreds of years, a protagonist has always been barking at him and attempting to harm him, but just couldn’t kill him.

When he spent his days bedridden like a dying man, his life was no better than that of the dead.

People respected him, feared him, secretly cursed at him, but he just wouldn’t die!

But he, the ultimate BOSS, has become an insignificant cannon fodder only to be manipulated and destroyed?

That’ll never happen.

A certain green-eyed man: Cutie, come into my arms.

Qingyun: Heh heh, Lao Zi will teach you how to behave.

*Ding* the world’s most ferocious little cutie has come online~

- Description from Novelupdates

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

Dr Dalton Wyatt, a world renowned Scientist and Inventor is transmigrated to the body of a high school student Dalton Wyatt who committed suicide due to unfortunate circumstances and complicated life.

A man reincarnates in the body of a boy who suffered a tragedy, only to realize that he is in the world of My Hero Academia. What's even stranger is that his quirk seems to have the abilities of Nen and Haki.