I Don't Like The World, I Only Like You - Chapter 7: Three Small Things

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

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

Born at the lowest grade, nobody thought Percy would amount to much.Everything changes when his bloodline manifests in an unexpected way, letting him possess random bodies across the cosmos. Snatching all sorts of advantages - like a second mana core - Percy can finally claim the resources and respect he's been denied.Yet, reaching the top won't be easy. Not every journey yields a valuable treasure, and neither the warring Houses nor the invading gods will wait for him to grow...***What to expect:- Weak to strong male MC- Daily releases- Fast paced with frequent powerups- Fantasy setting with magic and a system- Isekai elements (Percy often possesses random bodies on distant worlds)- Western cultivation elements (Cleansing mana core to extend lifespan)- Morally grey MC (Willing to break a few rules but not a scumbag)