Leveling Up And Becoming Undefeatable - Chapter 12 - F*** Your Ancestors

Lieutenant Jack Fritz is a self centered American man of German descent. He like many joined the United States Navy in hopes of getting an easy life and easy money. In fact getting money and taking it easy is all he has ever really wished for in life.However life seems to have other plans in-store for Jack as he suddenly finds himself at the beginning of World War 3. Though his fight does not last for long as he is suddenly blown to bits by a missile and sent into the afterlife, but instead of going to heaven Jack is dragged to another place where he is given another chance at life by some fiery demon for a price.Having been given no other chance Jack does as the demon says and earns himself life again. Though he doesn't return to his original world, but a medieval one. With no guidance and no higher purpose given to him he simply decides to do the best that he can within this new world of his. This time he will for sure earn that perfect life of his and possibly a lot more.But little does Jack know his fate is not his own and there are many sinister things in-store for him. Also the world he finds himself in is not a safe or simple medieval world, but one beset by dangers from all sides that are already little by little driving humanity towards its extinction.

This story is about a rookie researcher, who was forcefully dragged away from his restful life, compelled into facing various killers and zombies, always having to risk his life at the brink of death, and finally becoming an advanced researcher that is acclaimed by all. And throughout his adventure, he met an alluring(?) killing machine, who he started to have fantasies on after they had an accidental kiss…

Xiao Yan: Did I fall for him? But he’s a man!

Maya: Who knows…. maybe it’s the other way round?

- Description from Novelupdates

Sky is not born of Shen Huan, millennium is like night.

This is a rebirth who wants to release himself, and has an interesting life story after getting a less serious system.

- Description from Uukanshu

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