The Rise of Otaku - Chapter 336 - The Battle of Two Rulers.

“You’re the moonlight that lights up the night’s darkness~

This book was inspired by My Hero Academia: Adaptation“Who decided being quirkless means you can't be a hero? Those are just rules made by people who never tried to break them.” When a battle-hardened warrior dies in one world and awakens in the body of a quirkless boy in another, the rules of heroism are about to change.Armed with combat experience from a darker realm and an iron will forged in warfare, he sets his sights on U.A. High School - the pinnacle of hero education. But in a society where superpowers are everything, his approach to strength might just shatter the entire system.Behind a gentle smile lies the mind of a warrior. As he builds his power through unconventional means, one thing becomes clear: rules were meant to be broken, and this world's definition of “hero” is about to be rewritten.Sometimes the strongest ability isn't a quirk at all. It's the will to change everything.

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

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.