Citadel for All: The Only Unit Angel at the Start of the Game - Chapter 553

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

- Description from novelupdates

Lee Jin Woo once lived a dismal life.
He lived pitifully on a day to day basis in his five-pyeon studio filled with mold.

Then, one day, he died in a sudden fire.

When he wakes up, he finds himself inside a novel.
But there’s just one issue…
He had become the novel’s villain!

Kamishiro Homura is a hero who once by himself exterminated the another world invader that destroyed the military all over the world. However his extreme strength made the influential people ostracized and exiled him from the society with false accusation of [Traitor] attached to him. A few years after that, for an unspecified reason Homura entered the magician academy and he looked after the girls that were ridiculed as the [burden platoon]…!? This is the raise of the curtain of a fantasy tale of the unrivaled and invincible young man where not a single ally or enemy can keep up with him, the young man who sooner or later will be extolled as the messiah by the whole human race!

In the near future, a space channel connecting the other world suddenly appeared on Blue Star, and a large number of other world monsters poured into the homeland where human beings depended for survival.

Human civilization has shrunk sharply and had to hide in the base city to survive.

Only warriors can lead human beings to open up living space and regain lost land.

However, martial arts requires talent, and not everyone can become a martial artist.

People with outstanding martial arts talent can not only advance quickly and break through limits, but also optimize their exercises and benefit future generations, and are admired by all mankind.

By chance, Lu Heng discovered that his martial arts talent could continue to evolve…

- Description from novelbuddy