Zero no Tsukaima - Volume 21 Chapter 9

“Look, boss, that red dragon lacks dragon's might, and it doesn't even know how to breathe fire. Let's take it down and make a fortune,” said one of the adventurers.At that moment, the lethargic red dragon opened its eyes, looked at the adventurers appearing before it, drew a forty-meter sword, and deployed techniques such as Sword Mastery, Samadhi True Fire, Eighty Nine Mystical Powers, and Law Heaven and Earth...The world became quiet again, and the red dragon rolled over and continued its nap.This is the story of a red dragon who, after years as an overworked employee, finds himself reincarnated in another world.Devoid of the intrinsic knowledge and natural abilities of dragons, it wields other formidable skills.

What the heck? She, a famous doctor from the 23rd century, turned into a village peasant girl of a different world!

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