Fleeing from Konoha - Chapter 138 - 81:

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.

I transmigrated into a novel and became the villainess, Serina who comes from the noble Ducal Melford family.

As a well-to-do character, I tried to mind my own business, but the story had other ideas. A self-proclaimed mother brought back a boy – the duke’s heir and a genius wizard – intent on brainwashing and blackening him.

The contents of brainwashing are two things:

1. Obey our family.

2. And fall in love with Serina.

Thanks to that, the brainwashed twisted yandere is obsessed with me…

I can’t do this. I have to undo the twisted character’s brainwashing!

By the way, what’s this situation?

“Now that the brainwashing is gone, I’ll do as I please. So Serina, please, let’s do our best.”

I’ve solved his brainwashing… but why does he seem even crazier than before—

Did I make a mistake?

“Welcome to Perfect Life Simulator!”

“You can choose to simulate your own life or someone else’s life to find solutions to many life problems!”

…

A watch handed down from his deceased parents allowed Su Wu to start a future life simulator.

He thought that he could really use this simulator to lead a perfect life without regrets, but unexpectedly things developed in another direction.

In the future, as long as there is light, there will be evil spirits that kill people;

Hanging in the sky and covering a city, it leaves a city without red lanterns of living people;

The scarlet eye that can use a mobile phone to spy on the specific location of others…

Will such a future really come?

…

“you are dead.”

“This simulation is over.”

- Description from novelbuddy

When her father passed away, her mother married into a large family. She thought it'll be a new beginning of her life, but it only brought her an substitute marriage to a disabled husband her step-sister didn't want.On the second day of their marriage, the noble and aloof man said indifferently, “Divorce or live as a widow, choose one.”She pulled off his suit pants and touched his firm and sexy thigh, “I choose the third option!”Latter, she used her medical skills to healing and saving people, including her disabled husband, who turned out to be a hidden billionaire!Nobles and celebrities sought medical advice, flocking to her like ducks.Those who humiliated her regretted it deeply, begging for mercy on their knees.The billionaire smiled proudly, “My wife is a treasure, only her husband knows it!”She rubbed her waist and gritted her teeth, “Didn't you say that you wanted a divorce and warned me to stay away from you?”