Naruto: I am Uchiha Shirou - Chapter 414: Naruto: I am Uchiha Shirou []

It’s a affair between a loyal dog servant and his master.

- 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

Ye Fan accidentally obtained a billion crystal technology system, and since then, he has become out of control.

Android: You do n’t even have a mobile phone system. I want to make it impossible for you all!
Ye Fan: Sorry, I researched it out, it seems to be more powerful than yours!
BMW Benz: Our engines are famous all over the world!
Ye Fan: Sorry, I do n’t have an engine, I only have magnetic levitation, and the speed is only a few times that of yours. Do n’t worry, take your time!
…
Enemy: Is he still human?
Who can stop this!

- Description from Qidian

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.