I, the grandson of Garp, scare Luffy with a ghostly back

Once through the pirates, Lu En became the son of Monkey D Dragon. He had a grandfather named Monkey D Garp, and an unreliable and nervous younger brother named Lu Fei.
Fortunately, the ghost back system is activated!
The completion rate of ghost back is 10%, and the effect of cultivation is increased by 100 times!
The completion rate of ghost back is 20%, and the effect of cultivation is increased by 1000 times!
……
One day, Lu En, who had become a ghost, appeared in front of Luffy who was clamoring to go to sea, and scared Luffy to tears on the spot.
Luffy: "The pirates in the sea are all monsters like my brother? I don't want to go to sea!"
Garp: "For a long time, the two boys, Long and Luffy, have small arms and legs. I really doubt that they are not my son and grandson. Like Lu En, they are the grandsons of this old man!"
Warring States: "The strongest creature in the sea, land and air is Kaido? No, it's Lu En!"