Under the Oak Tree (Web Novel KR) - Chapter 256

Alex was an ordinary person with the dream of one day being transmigrated to a magical world.

But what he didn't expect is that he would be transmigrated to a world much more than that, a world he knew very well, but instead of being given a system that would empower him, he was given a system that allowed him to make games, and the more people played, the more powers he would get.

Tony Stark: I hate this! I can do in real life everything this Watch Dogs guy does, but why can't I stop playing?

Hulk: HULK HATES DARK SOULS!!! HULK SMASH DARK SOUS ARRRHHHHGGG!!!

Nick Fury: If any agent can't complete the Hitman game by next week, that agent will be fired from the Shield!

A world of superheroes, but who controls everything is "only" a game developer.

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!

Once through the pirates, Lu En became the son of Monkey d Dragon, a grandfather named Monkey d Karp, and an unreliable and neurotic younger brother named Luffy.

Fortunately, the ghost back system is activated!

The completion of the ghost back is 10%, and the training effect is increased by 100 times!

The completion of the ghost back is 20%, and the training effect is increased by 1000 times!

…

One day, Lu En, a ghost-backed master, appeared in front of Luffy who was shouting to go to sea, and made Luffy cry on the spot.

Luffy: “The pirates in the sea are all monsters like my brother? I don’t want to go out to sea!”

Garp: “For a long time, the two boys, Long and Luffy, with small arms and calves, I really doubt that they are not my sons and grandsons. Like Lu En, they are the grandsons of the old man!”

Warring States: “The strongest creature in the sea, land and air is Kaido? No, it’s Lu En!”

- Description from novelbuddy