MTL - My Master is a Bug - Chapter 487 you wait

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates

30 year old Lu Ziwen was born in poverty and after struggling for a lifetime, he is finally able to perform in the Golden Hall symbolizing the highest honor. However, an hour before taking the stage, he was killed by his lover.

In a romance novel called “The Secret Lovers of the Academy” the male lead would often torment his fiancée–but wait, why did she cross into this world to become his fiancée, the villainess, instead of the heroine?

Louise Sweeney found the perfect solution to escape the misfortune of being the villainess: “Your Highness, I just want to tell you that we don’t have to be tied with our engagement. We weren’t even officially engaged, right?”

But what was wrong with the male lead’s reaction? To her suggestion, he replied “But our engagement wasn’t false, don’t you agree?”

Beings that create and control monsters and demons, beings that build and reign over malicious labyrinths, the chosen individuals to possess an overwhelming Unique Skill… They are the Demon Lords.