Naruto: The Strongest Kakashi - Chapter 381 The Land Of Flower

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.

In the past, the giants of the heavens and the gods were destroyed after the reincarnation of the world! Cruel curse, eternal hatred, Tan Yun is determined to never sink again! For the sake of loved ones and relatives, from now on, step on the corpse of the enemy step by step to surpass the peak! Defying the sky, killing all worlds, I am the only one!

- Description from novelbuddy

All it takes is one monster for the world to go to ruins.Life as Nadine knows it goes to shit and she has to accustom herself to life underground, that is until an accident forces her out into the real world.Caine has no idea why he saved Nadine.She is everything he hates- rich, spoiled and entitled- and yet, he couldn't just let her die.Living outside is hard enough without having to save someone else and yet, he does it with Nadine.Thrust into a world that she has no idea how to navigate, Nadine is forced to rely on Caine.Her life is literally in his hands.They soon realize that maybe the monsters are the least of their worries.

‘Yoknapha,’ an international and well-known villainess actress, is suddenly transmigrated into a series she once starred in as ‘Bai Yu,’ a daughter of the senior chancellor. If this world follows the same plot of the story she knows, she will always lose to ‘Bai Hua,’ the heroin.

Nevertheless, if she loses this time, the one who will receive disgrace is not Bai Yu, but Yoknapha herself. That is why this time she will not surrender to the dreadful fate!

If it is determined that a heroine will end up with a hero in every love story, this one has to be different. She will be a villainess who gets to be paired with a hero herself. If wicked deeds bring what she needs, she will stay evil to the end!

That will be easier if a mysterious man Bai Yu does not remember exists does not appear and makes her heart pound like this!