Combat Maid Harem - Chapter 510

In the year 2057, the world has become a corporate-run utopia for the super-rich, and a hellhole for all the rest. Catherine 'Cat' Leblanc is an orphan that is about as far from super-rich as one can be. When the Incursion alarms start blaring and the sky starts raining hungry xenos, it's just another blemish on an already piss-poor afternoon. A cyberpunk magical-girl alien-invasion LitRPG.It’s exactly as wild as it sounds.

I just want to be different, no one can guess what I want to do, the more mysterious the more powerful.

- Description from novelbuddy

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.