Beast Taming: Starting From Zero - Chapter 553: Rules

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.

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――

The young lord of a small and weak country saves a dragon beside the sea one day.

This is a world shrouded in darkness.The spreading Black Fog corrodes every living creature.The only protection for humanity lies in fire.But as the dark Epoch approached, the fires slowly extinguished.Countless strong Kingdoms became dens for Dark Monsters, humans lost contact with each other, and survivors trembled in the faint solitary light.Until Rod came to this world.“Damn, what's this cow and horse stuff, is it edible?”“This Soul, it's delicious.”“As long as the will of fire remains unextinguished, I believe, one day, humanity will once again illuminate this world and burn all spectral vermin to ashes.”“Even if I'm mired in darkness, bearing the Dream Realm, I can still support this world!”“We've won!”——The world is about to fall, the Abyss looms at our side.And I will raise this Unique flame to light up the world.Yes, I am the last King of Darkness.But...Hello? Anyone, save me.