The Daily Life of the Demon King - Chapter 367: The King of Curses or Just an Ordinary Thief."

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.

Heed my call! O’ Dragon of Eternal Sin, the Progressive Disaster, the Forerunner, the Land of Eternal Peace, the Flames of Soul Burning, He Who Owns The Deep Soul, the Sound of Origin, the First Cause of All Things, the Principle of Circles… o’ great Negary, your servant calls for your return!

“Epoch” is a world where steam, magic, machinery, alchemy, and extraordinary power coexist.

When Luke, who had traveled over, covered his head and was pointed at his head by an imperial agent with a gun, he decided to tell a lie.

So he became the detective of the Secret Affairs Bureau of the Cape District of the Golden Shield Empire.

Luke, who is familiar with the plot, just wants to save his life in this chaotic world, and get some money and materials to use secret words to enhance his strength.

He robbed, kidnapped, blackmailed, and committed crimes with a plot strategy, but he never thought that he robbed an imperial gold ship, and how did he solve the largest smuggling case in the history of the empire?

As a “fake” detective, holding a promotion order, Luke felt very embarrassed…

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In the virtual world, power is what you seek. In reality, it’s the pursuit of truth.

But the game is not actually a game.

Evolution!

- Description from Novelupdates