Face-Slapping System - Chapter 9 I Should Be Happy

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

When the Terminally Ill Noble Allenbert woke up from his fever, he realized that he was the reincarnation of Karzan, the mad dog who roamed the underworld.…But something about this place doesn’t feel right.“Allenbert, nobles need secrets and darkness.”The sinister and chilling schemes of his brother, like a snake, are suffocating him from all sides.“You’ve been causing quite a stir lately.”The powerful and authoritative eyes and ears of the head of the family are hidden everywhere, watching him.“…When will I see Mother?”Meeting his mother, who has secluded herself due to a mental illness, seems impossible.“But it’s okay.”Karzan failed, but Allenbert’s journey is just beginning.“Two lives, two revenges.”There’s no mercy.I’ll pay back with interest, and make sure it’s done properly.

This is a world where humans, demons and mysterious beasts coexist.

Humans cultivate mysterious qi. Demons cultivate corporeal bodies. Mysterious beasts cultivate soul perception.

A legend says that in the middle of an endless rainforest, there are extremely powerful existences; they are called demon kings.

Some demon kings have a tyrannical corporeal body, some are experts in illusions.
Some demon kings are proficient in magic, some can even move mountains.
Some demon kings are able to sense things thousands of miles away.

These demon kings rarely appear in the human world. Even if they emerge in the human world, they would reincarnate in human form; assimilating with mankind while seeking to breakthrough realms…

- Description from Novelupdates

To correct the mistakes of his past, a young man is forced to narrow the space between science and witchcraft, as he ventures on a quest to save his world from complete destruction.