Reincarnated into Madness: Yandere Family's Unwanted Slave - Chapter 19: VOLUME 2 - 2: Separation anxiety and Shattered illusions.

A polite and lethargic boy was reincarnated in another world as a vampire bishoujo.

I was thrown into a novel that hasn’t even been completed yet (and turned into a girl…), guided by the omnipresent voice of the unreasonable, amateur Author as he writes the web novel. I have no idea what’s going on, so I have to stick close to the main character to make sure I don’t hit a bad end…Why are you treating only me like this!I’m not suspicious, believe me.I’m a harmless person.“A villain? Not at all.”

Beautiful doctor of Chinese medicine, Yu Gangan woke up from a coma one day to a cold, mysterious man. “Excuse me, you are…?”

A pair of profound eyes focused on her and replied, “Fang Zhihan, your husband.”

Did this man take her for a fool? He was obviously a fraud!

A little while down the track, he pulled her into his arms and whispered beside her ear, “Who am I?”

This time, Yu Gangan froze and replied, “Fang Zhihan, my husband.”

If he was a patient, then she was his sweetest medicine…

- Description from Novelupdates

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