This is really not mechanical ascension - Chapter 13 - : Upgrading the Air Hammer and Dagger

"When will people understand.... I'm only half insane?"

Zhang Xuan traverses into a foreign world and becomes an honorable teacher. 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 weakness would be automatically compiled. Thus, he became formidable.

“Emperor Haotian, why don’t you like to wear underwear? To think that you’re still an emperor, can you pay more attention to your image?”

“Fairy Linglong, if you continue to suffer from insomnia, you can always look for me. I have a way with lullabies!”

“You as well, Qiankun Demon Lord, can you cut down on the garlic? Do you want to stink me to death?”

…

This is an incredible story about the heritage between teacher and students, cultivating and guiding the world’s strongest experts.

Kamishiro Homura is a hero who once by himself exterminated the another world invader that destroyed the military all over the world. However his extreme strength made the influential people ostracized and exiled him from the society with false accusation of [Traitor] attached to him. A few years after that, for an unspecified reason Homura entered the magician academy and he looked after the girls that were ridiculed as the [burden platoon]…!? This is the raise of the curtain of a fantasy tale of the unrivaled and invincible young man where not a single ally or enemy can keep up with him, the young man who sooner or later will be extolled as the messiah by the whole human race!