Chronicles Of Gu Hai - Chapter 20 - Bet

One day every human on the world suddenly receives a mail claiming to enact the World Salvation Project. Half in doubt Kurosaki Shion, a diligent university student and loner, follows the mail’s instructions, becoming one of a million Demon Kings governing his very own Domain in the new world.

*** This is a post-apocalyptic story containing many fantasy elements. It is a somewhat dark tale following Shion as he grows while aiming for the unification of the all too sudden new world. It has many game-elements bolstered by strategical thinking while at the same time providing funny moments and romantic encounters.

I, the mighty Telepath Starlord, got banished into the mortal world. The days in the mortal world are much better than those in heaven! Everything is here — money, authority and most importantly stunning beauties! I am from a rich family. Yes, I am indeed wealthy now. The kind of wealth where you would not want to displease me. Domineering CEOs, military big shots, business geniuses, you name it — I know them all! I know everything you are thinking about. You can’t defeat me anyway, how are you going to go against me? A century in the mortal world is only equivalent to a hundred days in heaven.
As an urban banished immortal, I will enjoy the heck out of my time in the human world and a huge commotion would arise in heaven!

- 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 became a scientist for an evil organization.…But I’m too competent.