The Unsuccessful yet Academically Unparalleled Sage
English: The Unsuccessful yet Academically Unparalleled Sage ~A Cheating S-Rank Sorcerer's Post-Rebirth Adventurer Log~
Japanese: Rakudai Kenja no Gakuin Musou ~Nidome no Tensei, S-Rank Cheat Majutsushi Boukenroku~
Romaji: 落第賢者の学院無双 ～二度目の転生、Ｓランクチート魔術師冒険録～
After reincarnating in a different world, the great sage Ephthal spent all of his life researching magic. However, he who had aimed to reach the summit of magic, knew of the limits of his talents and fell into despair, thus closing the curtain to his lifetime.
However, 400 years later, he reincarnated for the second time and enrolled in a magic academy using the sorcery and knowledge he acquired from his previous life. As if to sneer at the state of magic that had been in decline for the past 400 years, he easily invokes legendary class magic!
With overwhelming power, the entire world will kneel before him.
The story begins with defeat of the demon king, protagonist, a 40 years old magician, is a part of the hero's group as Sage of Wind. Protagonist feels that his magical ability is inferior to the other three, young and more talented sages. Yet the King sees fit to grant him the same recognition as the other three. Fast forward 15 years, protagonist is older now and slowly dying of some kind of disease while rising his adopted daughter Merlin. Who just so happen to be the daughter of the demon king..... So far the story sounds quite similar to The Reincarnation Magician of the Inferior Eyes. Shortly after protagonist dies and goes to heaven.
Goddess: Howdy, long time no see.
MC: Hello, so its this place again.
Goddess: Yup, ready for a third time?
MC: Yeah, send me back in, this time I will become the strongest for sure!
Goddess: Wanna grab your reincarnation bonus?
MC: I don't need no cheat skills! (except for the skill that allows him to reincarnate after death)
Goddess: You sure? Alright, good luck then! winky face
Protagonist is reincarnated as part of his bloodline, 400 years in the future. The world has changed greatly and his descendants has become cruel and corrupt. His adoptive daughter Merlin is still around and has had some children of her own. According to legends, the three sages that defeated the demon king are also kicking around. But people's proficiency in magic has declined greatly. Protagonist starts off by clearing the house and enrolling into magic academy while keeping his identity a secret.
Seems like the web novel has been taken down by the author.
I would pick up this one for sure the manga is a good read