I Don’t Want To Defy The Heavens - Chapter 1 - Ok then scram

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.

In the world of Norse mythology, a human boy falls in love with Waltraute, the fourth Valkyrie sister. He wishes to marry her, but Waltraute gives him an impossible challenge to deter him.

Nevertheless, the boy is determined to carry out the dangerous task and to marry Waltraute afterwards.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

- Description from Novelupdates

Zhou Xu, who had just graduated from college, suddenly received a call from his father.

“My son, since you have grown up, there are some things that a father should tell you.”

Zhou Xu: “Dad, how do you speak in a succinct manner? Half white or not, what TV series are you watching?”

“My son, it’s a showdown for my father. For my father, you are a giant of the devil. You are the son of the devil.”

Zhou Xu: “…Dad, I’m hanging up, I’m busy.”

“Wait, there’s one last thing. Aren’t you too young? Your mother arranged a blind date for you. See you.”

Zhou Xu: “Who is it?”

“Like you, the devil goddess at the opposite door.”

- Description from novelbuddy