My Gu Can Cultivate on Their Own - Chapter 239 - Set Off!  

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

Once upon a time, a hero had been summoned to a different world in order to defeat the demon king. After the war stretching 3 years ended the commendable hero slew the demon king. And he was forcibly deported back to earth after being dismissed.

Such bullshit!

Elves in addition to beast race, dwarfs and demon race. Even though I wanted to make a harem in the different world I saved! My dream will not come true on earth, where there is no magic at all. Thus, the hero returns on his own. Without the blunder of being extradited to earth this time, he will build a harem of his own in a different world.

This novel is also known as Gu Daoist Master

Humans are clever in tens of thousands of ways, Gu are the true refined essences of Heaven and Earth.

The Three Temples are unrighteous, the demon is reborn.

Former days are but an old dream, an identical name is made anew.

A story of a time traveler who keeps on being reborn.

A unique world that grows, cultivates, and uses Gu.

The Spring and Autumn Cicada, the Venomous Moonlight Gu, the Wine Insect, All-Encompassing Golden Light Insect, Slender Black Hair Gu, Gu of Hope…

And a great demon of the world that does exactly as his heart pleases!

—

*Gu (蛊) referred to poisonous insects in various cultures in South China while in folklore Gu spirits could transform into all kinds of species.

- Description from Novelupdates

He was once the most feared villain in the empire, a master of manipulation who wove chaos from the shadows. Ruthless, untouchable—until the day he was betrayed and executed by the very man he sought to control.But death is not the end.He awakens in the body of Lady Elara Valcrest, a fragile noble girl doomed to be a pawn in political games. Stripped of her former power, she is forced into an arranged marriage with none other than Cairon Everhart—the man who once killed her. He does not recognize her, but she knows him. And she will never forget.To survive, Elara must play a new game. One where deception is her only weapon, and trust is a dangerous illusion. She must outmaneuver her enemies, uncover the truth behind her execution, and reclaim the power she lost. But as she navigates the treacherous world of court intrigue, one question lingers—Was Cairon truly her greatest enemy? Or had she been blind to an even greater threat?Time is running out. The villain has been given one last chance. And this time, she refuses to lose.