King - Chapter 1443 - 8: The Pope Should Use Open Strategies_2

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.

Within the red tent, under the passionate eyes of the man on top, she was forced to make love and three thousand black strands turned to white.

One day, Raizou ​​Takakura, an average salaryman, had a Heart Attack and his life ended that day.

But, he got a second life, in a different world.

Reincarnated with strong skills―― wasn’t what happened to him, instead, he was reincarnated as a foot soldier in a small country, Highserk Empire, which was surrounded by large countries.

With a new name, Walm, he was thrown into the frontline of war.

Covered in blood and the stench of death, along with his comrades, he was slipping through life-or-death situations.

An adventurer party with members that could use powerful magic, transferees with overwhelming power called the “heroes”.

In a deadly battle with them, Walm gradually developed his talent as a warrior which would’ve never awakened if he were to stay in times of peace.

While his eyes becoming dark and muddy over time――

In a certain world, there was someone who excelled in magic combat, people called him 『Sage』. Seeking the strongest combat art, he devoted himself to research every magic and combat arts in existence. And the conclusion he arrived at was very cruel, 『My body is not fit for magic combat』. Yet he didn’t give up. He sealed his own soul with a magic art, and was reborn in a far-off future. And the magic theory in the completely changed world he saw there was of unbelievably low level.