My Yandere Succubus Daughter is Mommy-Warrior's Natural Enemy - Volume 1 Chapter 44

A mental patient, or a born policeman?

A peerless genius, or a master of crime?

There are cops who are least like cops, and there are criminals who are least like criminals.

Neither good nor evil is absolute.

It is a grey world we live in.

- Description from Novelupdates

Sanctora has known peace for generations—too long, perhaps.Built upon ancient ideals and ruled by a council bound to tradition, the kingdom believes itself untouchable. But beyond its tranquil borders, something has awakened. Whispers of vanished heroes, creatures long thought extinct, and shadows that no longer sleep begin to creep back into the land.Liora never wanted to be a hero. Orphaned young and shaped by loss, all she’s ever known is survival base on love and kindness. But when a brutal invasion exposes the kingdom’s deepest vulnerability, she’s thrust into the heart of a battle far greater than herself. Her light-element magic—once dismissed as minor and passive—may be the key to a new era of power.As Sanctora struggles to adapt, Liora must decide whether to follow the path laid out by those before her… or blaze a new one through fire, blood, and truth.Epic, emotional, and filled with slow-burning revelations, Ancient Beast Summoner is a story of legacy, buried power, and the girl who just might change everything.

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.