MTL - Mermaid Feeding Rules - Chapter 75 , two in one

He had crossed into the dark, ruthless Wizard World.Lucien found his system somewhat different from the usual golden finger.System upgrade points? Chip activation?None of these, but rather becoming a role model, transforming into a nurturing breeze:Teaching students knowledge, receiving advanced knowledge in return.Caring for and maintaining students, earning generous rewards.[Your student has mastered the Magic Potion “Kuru's Cough,” congratulations on acquiring the improved formula “Kuru's Cough - Enhanced”!][Your student has mastered witchcraft “Fireball,” congratulations on learning witchcraft “Greater Fireball”!][Your student has successfully crafted the wizard's tool “Pale Mask,” congratulations on acquiring the wizard tool’s manual “Revised Pale Mask”!]Initially, Lucien was resistant.But after experiencing what it was like to teach disciples and outdo them, Lucien felt he had completely transformed into the form of the master system.This thing, isn't it much more useful than something called Cheating Device?

“Shit, why this guy!?”Of all the unique characters he could’ve transmigrated as, it had to be the bastard instructor.Vanitas Astrea.A third-rate middle game boss, who was dismissed from the University after severe allegations, losing his teaching profession and ultimately, exiled from the Empire.“.....How did I even get here!?”Vanitas must now circumvent his way around this new world, confront his past, mend broken relationships, and prevent looming tragedies that would lead to his demise.

Shen Yuqing and the Emperor had a secret arrangement––

She was his pampered consort, and she would hit wherever the Emperor directed her to strike;

The Emperor “loved and favored her forever”, and she could do whatever she wanted.

Later, she set her eyes on the Empress who had the same type of marriage only in name…

- Description from Novelupdates

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.