Maken no Daydreamer - Chapter 33 – Exceed Hopper

She was the Fifth Young Miss of the revered General’s Residence, but was seen to be useless as trash. Promiscuous and flirtatious to a fault, she was finally killed by mistake under the hands of the attendants of the man she was chasing; She was a genius favoured by the Heavens but ultimately murdered by an insidious plot and all who shared her bloodline pursued and exterminated which caused her to lust for revenge to be paid in blood. The day the genius had unwittingly taken up the body of that useless trash and opened her eyes, her fate had completely changed!!!

Refining elixirs and the smelting of weapons were tough?
That did not daunt her.

Beast Tamers were rare?
She had easily gained the title of Emperor Beast Tamer!

Forced marriages!?
Men being arrogant because they are good looking?
She stretches her hand out and easily pulls devilishly handsome men to her: The Demonic King brothers would easily take their place. A devilish glance, a slight shimmer of movement, and that man would suddenly disappear the next moment. He turned back around, his devilish smile alluring: “Let’s continue with the topic, let’s have a child!”

This is another interesting story with transmigrating and very fun filled characters that will delight you.

- Description from Novelupdates

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.

This was a fragmented and disorganized world, this was a place that had been forgotten.