The Demon's Bride - Chapter 35: Working As a Maid, The Lords Of The Land-I

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.

“Shit, is this really how I turn out?!”In the time of war he was known as the Body Flicker, Forbidden Magic Maker, and the Golden Blur.Arthur Vaelthorne.He had so many titles that it was unsurprising that the empire was the side that won the war, all because he had participated in it.A man that had the potential to become the strongest, rivaling the old powers, and the talent to back it up....Only ended up as a hidden boss in a popular game, meeting his end at the hands at one of his own students.A powerful hidden boss, unfortunately he had the fate of any other boss: Beaten by the protagonist.Now, with a second chance and the memories of one of the game's top players, he has a chance to rewrite his fate.

Entering the mortal world for a hundred generations, do not compete for the youth of one life, but only for the day and night of a hundred generations.

Seeking immortals in the world of mortals.

My name is Li Qing. I have escaped from the mortal world in the third life, entered the Tao in the ninth life, and become immortal in the hundredth life.

(longevity stream, non-simulator, non-reincarnation rebirth)

(Bai Shi Shou Yuan, One Life Life)

- Description from novelbuddy

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.