Gekitotsu no Hexennacht - Volume 2, Chapter 8: To Where It Simply Is

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.

This is a story about love, friendship, ambition, betrayal and fearsome weapons.

Escaping from the wedding she dreaded with Crown Prince, Aed Ruad, Princess Anastasia ended up becoming the captive of the Lore's most dangerous man, Prince Ileus.

The day of marriage. Lifting the sedan chair to the door, he lightly lifted the sedan curtain, but he saw no newcomer, only a piece of paper pressed under a stone.

Looking at her flamboyant font, his thousand-year-old pupils faintly spurted out a few flames. good very good. On his perfect and impeccable face, there was a faint smile, not angry but smiling.

However, no one saw the hidden chill in that smile. That woman dared to run away from marriage, he would let her know the consequences of doing so.

- Description from novelbuddy