Ze Tian Ji - Chapter 454 – The Story of Bear Cubs and Swords

I am the sword.
Killing a man amidst a thousand miles, no one dares take ten steps.
Killing a man amidst a thousand miles, no one can take ten steps.
Killing a man amidst a thousand miles, ten steps? Not possible!
I am the sword, the sword is me,
On the path towards heaven, each shall wield their own.

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.

#Expect a big Harem but MC won't mindless collect women on a whim. There's deep mature content. Beware!After getting rejected and humiliated by the very woman he's ever loved—and publicly dumped during lunch break in front of half the school while holding a giant teddy bear, blue roses, and a handwritten love letter titled “My Heart in .mp3”—Jayden Cross thought life couldn't get worse.Then he wakes up with a system talking in his ear.[Ding! Welcome to the Ultimate Copy and Paste System!][Function Unlocked: 10x Copy and Paste!]Now armed with a divine-level Ultimate System Jayden begins rebuilding his life with just copying and pasting everything and gets 10X more!What the world, the system, and the universe had shattered without remorse, only the Ultimate Copy and Paste System could restore. But it did not simply mend—it reimagined. It rewrote his broken existence into a force no storm could contain, only follow.

My name is Joelson, and I traversed across the world. I arrived at a continent of sword and magic and became a noble sorcerer.