Skeleton Knight, in Another World - Chapter 2Volume 1 -

Shen Shi obtained a trading platform that was based 3000 years in the future. Everything from the current age became antiques there and was worth a lot of money.However, he also discovered that the world would be invaded by aliens three years from now. Mankind would fall and the dark Galactic Era would thus begin.The world would then undergo enormous changes that it had never experienced in the past tens of thousands of years.Shocked by what would transpire, Shen Shi decided that he would first trade for a galactic warship.As such, a warship from outer space landed on Earth, stirring up terror among all mankind.The Earth entered the Galactic Era earlier than expected.

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

Demons are rampant, the court is corrupt, the human race is declining, demons are rampant, and the world is treacherous and haunted.

Martial arts masters are just more delicious blood food in front of monsters.

There has never been a savior in this world!

My name is Jiang Heng, and I am the one who runs amok!

- Description from novelbuddy

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