The Devil King of fast wear was a little sweet ( Machine Translation ) - Chapter 99 - 116 Cannon Fodder Master was going to attack 20

After dying in a tragic accident, Oscar was reborn into a lowly tribe in an ancient world of great magic where only the strongest survives. Following the decimation of his family, his only solace comes in the form of a remnant which resides in his body.Live the tale of powerful warriors and deadly monsters, and tell the story.

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.

I returned to the past to become an actor, instead I reincarnated as a Third-Gen Chaebol (rich conglomerate family).[Winner of the 7th Korean Web Novel Competition]

Abandoned at birth in a humble stable, Shirone was raised by commoners—but he was anything but ordinary. Blessed with remarkable insight, he taught himself to read at a young age. A fateful visit to the city introduced him to the wonders of magic, igniting an unshakable dream of becoming a mage. Yet, beneath the city's dazzling facade lurked a ruthless social hierarchy, where power and privilege crushed those who dared to rise above their station. As Shirone uncovers the world's darkest secrets before even coming of age, one question remains—can he defy fate and claim his destiny as a mage in a world determined to keep him down?