Maou na Ore to Fushihime no Yubiwa - Volume 3 Prologue

Kai of the Sorcerer’s Tower is one of the last mages left, barely surviving in a world ruled by creatures of the dark — where the era of mages ended, and most of the lands got contaminated with dead mana. To save his world and fulfil his master’s last wish, he put himself through a forbidden ritual, risking his soul being ripped into pieces to make his way into the past. In an era with abundant mana — an era yet to enter the Golden Era of Magic. Things go wrong, of course, as they always do, and he finds himself thousands of years before the world fell to mana contamination — in the body of a young lord, Arzan. All is not well, though, as the young lord was murdered by someone right at the cusp of a beast wave threatening the territory, while larger threats loom on the horizon. There was a lot to do for Kai to regain his former strength in this time of primitive technology, but then again, he might just be able to change that.

Song Yu Xi is a tasker.

The system told her that she has a great and glorious task on her shoulders – to save the world!

Song Xu Yi is dedicated to her work, remembering the first rule of the Fast-Travel Code of “no love”, and is dedicated to reforming the world-ending villain and strengthening the power of the protagonist, but she never thought that every world would develop in an unpredictable direction:
The beautiful and charming villainous movie queen hugged Song Xu Yi’s neck and breathed like an orchid: “Kid, why do you always blush when you see me?”

The sickly and delicate villain Omega raised Song Xu Yi’s chin: “My dear Miss Song, how does it feel to have an Alpha become an Omega?”

The cold and beautiful villain student sneered and put the five million check into her school bag: “There is no other way to repay the favor of funding, only the promise of your body.”

The villainous prince disguised as a man slowly tore up the peace proposal: “If you want to negotiate peace, you can let your Grand Princess Song Xu Yi come and make peace…”
System （(艹皿艹 )）: Say no to love and don’t fall in love!!!

Song Xu Yi ((╥_╥)): Sorry!

I blame the villain for being too beautiful, I couldn’t see her tears…

The love story of a hardworking wage earner tasker and a gloomy world-destroying paranoid villain.

- 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