MTL - Cultivating In Secret Beside A Demoness - Chapter 645 Devil: Explain it, I'm listening

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?”

“If the world stands in my way, if people threaten me or those who are dear to me, then I shall become the true darkness, the fear in their hearts that haunts them forever!”Lee Gaon was a professional gamer until one day she was framed as a cheater by a big gaming company and betrayed by those she held dear. Now she is known as Death Eater, a powerful dark entity in the game system world, slicing her enemies in half if they dare mess with her. Her path is now filled with blood and adventure as she desperately tries to find all who were dragged with her into this world—those who destroyed her life. She has only one goal now... “Revenge!”Content Warning:This work contains scenes of gore, violence, and strong language. Reader discretion is advised.

Katherine Zara, a single middle aged office worker, went about her day as she always had; wake up, go to work, come home and read or play games. However, today would be different. Before she left for work, her ex broke into her apartment and killed her.

When she woke up, she was given many choices. She could pick her new world, pick her starting point, and pick her system among many other things. And so Katherine decided to become a servant to a villainess.

Follow Katherine as she serves her petty, demanding mistress in a world of swords and magic.

Additional: The Female Lead (Katherine) will be submissive to her mistress, but will be cold towards others. I plan on having some action, but mainly this will be a story about Katherine serving her mistress and leveling up her system.

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.