Toaru Majutsu no Index - Volume 2, Chapter 1: A Tower of Glass. The_Tower_of_BABEL.

Unlimited opening, unlimited power! The mutated mobile phone has a magical app download! All kinds of buildings, can rise to the sky, can sneak into the sea, can be hidden… hidden secrets of the big!

Tang Zhen’s ability to build a city is… Building a city, playing with explosives, crushing the ground and grabbing the ground.

Tang Zhenduan sits on the top of the mountain, and at his feet is an endless floating city, guarded by dragons, surrounded by angels, and countless giant guns stand in the sky!

In the depths of the ocean a million miles ahead, it is another big 6-level building that is waiting for his conquest!

- Description from MTLNovel

Legend says, that there is a great demon, who is the human kind’s public enemy. He is the galaxy federations’ nightmare as he wanted to conquer the whole universe. On the first day, he completely took out the human fleet, plunging them into disorder. On the second day, he declared that he will wipe out the whole federation. On the third day, he declared——that the hero who shot him in their previous battle must marry him, or else, he will destroy everything.

The galaxy federation president and the council members had a long meeting after that. They decided to dispatch a soldier, Wu Xing Yun, and marries him off to the arrogant demon. Wu Xing Yun was once a hero who fought for the nebula, and henceforth, he was tasked—— for the sake human race and the universe’s peace, to eliminate mistresses, settle his matters with the mother-in-law, and fix the man’s crooked ways.

Wu Xing Yun was very perplexed when he asked his commanding officer: “Sir, why did it have to be this way?”

Commanding Officer: “Soldier, bear in mind, that this mission of yours, is for the sake of the universe and mankind’s happiness. You must hold on to your husband, and fight other mistresses! Do you have the confidence to accomplish this task?”

Wu Xing Yun, stood straight, saluted, and instinctively replied: “Sir, yes sir! I will accomplish this task!”

- Description from Novelupdates

Kain, a young teenager, accidentally lost in a Dungeon and awakened a special system. A system that allows him to continuously return to level 0, using his level to add and increase his skill points. From there, Kain began his journey to find the truth of this world, and when he took off that mask, what he saw was...

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