Forced To Marry The Devil : A Crazy Love Saga - Chapter 22 - 22. Justice Seeking Markus

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- 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.

I never thought I could become a hunter.I never thought I would get the chance.But that wasn’t true.「 ‘Tower of Trials’ has selected all suitable candidates from Earth. 」「 Please select your difficulty. 」「The chosen difficulty will be directly proportional to your rewards. 」I was given a chance now.A special one at that.