Toaru Kagaku no Railgun SS - Volume 1, Chapter 2

The Celestial War!A war that has been ongoing since time!Pyrrhus, the human god isn't left out. He's known for his might and greediness, conquering many stars and sectors!Kyle Lin, a boy of Zekkoa becomes the recepient of a system; one which Pyrrhus has sent as a help. Forced to reincarnate into a magic world, he must grow stronger as the world is at stake.Kyle must free himself of being a pawn and take power into his own hands. Witness his journey to become an Omni Mage!

After 2000 years has passed, the ruthless demon lord has just been reincarnated! But his aptitude at an academy for nurturing candidates for demon lords is, “Inept”!?

Magic, eastern fantasy, cultivation, scientific technology…

Traversing into another world, Zhang Xuan finds himself becoming an honorable teacher.

Along with his transcension, a mysterious library appears in his mind.

As long as it is something he has seen, regardless of whether it is a human or an object, a book on its weaknesses will be automatically compiled in the library.

Thus, he becomes formidable.

“Emperor Zhuoyang, why do you detest wearing your underwear so much? As an emperor, can’t you pay a little more attention to your image?”

“Fairy Linglong, you can always look for me if you find yourself unable to sleep at night. I am skilled in lullabies!”

“And you, Demon Lord Qiankun! Can you cut down on the garlic? Are you trying to kill me with that stench?”

This is an incredible story about teachers and students, grooming and guiding the greatest experts in the world!

- Description from Novelupdates