Apocalypse: I Built the Infinite Train - Chapter 15: Devouring the Large Freezers

It’s a affair between a loyal dog servant and his master.

- Description from Novelupdates

“Brother Katakuri, I’m sorry, I don’t want to bear the name of Charlotte for a long time!”

“Ace, your flame is too weak!”

“Akainu, magma is dessert to fire dragons! Why don’t you understand this?”

The man who ate the dragon fruit, the traitor of the Charlotte family, sprinted towards the title of One Piece!

- 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.