MTL - Reign of the Hunters - v5 Chapter 39 reverse

A girl who calls herself a demon appeared before a timid student named Fumio Kijima. The girl claims to be a campaign girl from the demon world and she gives him the ability to “summon a room” from nothing but thin air.

At first he doesn’t abuse his power and uses it as a convenient ability in his every day life. But one day he is bullied by his classmates under a false pretext and is made to suffer. In the past he would have wallowed in misery and cried himself to sleep, but now he had a power to call upon.

“I will make them regret it!”

Using his powers to summon his “room”, he begins his era of confinement and brainwashing to achieve his goals.

Grandpa Yu often repeated beside the ear of Yu Zhen, saying that he(YZ) has a soul in his body. If he doesn’t properly train in asceticism, and raise then send away the powerful soul, in this lifetime he would have to live as a bachelor. In his next lifetime he would be reborn as a lifestock animal.

Yu Zhen played on his mobile and nodded. On the surface he replied, “Uh-huh”. In his heart he laughed, “hahaha”. Keeping his grandfather in the dark was amusing so the lie was repeated for over ten years without Yu Zhen getting tired of it.

After some years, Grandpa Yu passed away and a cold-faced handsome guy came to his door in a luxury car – with a household register in his hands.

…..

Yu Zhen: The soul in my body reincarnated into someone else’s body to demand repayment, what should I do!

- Description from Novelupdates

When people die, where do they end up to?I don't know about anyone else, but when I died, I arrived at the strangest Heaven of all times. And I got a chance to reincarnate with all of my memories!Jackpot!If you look away from the fact I had to reincarnate as a damn monster which is the lowest of all the bottom feeders? And I had to represent one of the worst goddesses ever!?And to make things worse, my “birthplace” was a freaking Dungeon! And not your everyday Dungeon with level 1 slimes and goblins, but a freaking Dungeon-turned-world-destroying-facility!Still, you gotta work with what you have. So see me how I survive in this crazy new world!!...But I promise I won't be mad if the bosses get debuffed. No? Damn...

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.