Lethal Stunner: Kicking Off with Five Beast Husbands - Chapter 6 Kittens Shed Fur Too

Takebayashi Ryouma, a 39 years old man with hidden past, found himself in a strange white room. The gods tell him that he has died and that they are sending his soul to a different world, a world where magic exists. After living alone for 3 years, his gamer soul loses its common sense and starts along crazy routes.

In a modern world, a professional assassin was murdered by her beloved and found herself revived in an ancient world as a general’s daughter with a weak physique. She was engaged to a prince, but because she did not have a nice appearance, her fiancé and sister attempted to kill her. Although she had to struggle to survive, there were also those who unconditionally loves her that supported her in her time of need.

What happens when a Powerful CEO in the Fashion World who already promised to marry his girlfriend, is forced to marry a woman from a lowly family, compared to his high-esteemed family background, against his wish?

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.