MTL - Shura’s Wrath - Chapter 773 Night emperor

The world is terrorized by the powerful Black Witch who has been sealed in the moon. Every ten years, the night of Hexennacht arrives and a chosen witch must battle the Black Witch in hopes of finally defeating her.

As the current decade’s Hexennacht approaches, a mysterious girl named Kagami Kagami arrives and meets Horinouchi Mitsuru, the daughter of the previous Hexennacht representative.

It takes place between Kyoukai Senjou no Horizon and the City Series, two other series by the author.

Beautiful doctor of Chinese medicine, Yu Gangan woke up from a coma one day to a cold, mysterious man. “Excuse me, you are…?”

A pair of profound eyes focused on her and replied, “Fang Zhihan, your husband.”

Did this man take her for a fool? He was obviously a fraud!

A little while down the track, he pulled her into his arms and whispered beside her ear, “Who am I?”

This time, Yu Gangan froze and replied, “Fang Zhihan, my husband.”

If he was a patient, then she was his sweetest medicine…

- Description from Novelupdates

When I opened my eyes, I was inside a novel.

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.