Battle and Sex Is All A Primordial Fiend Needs - Chapter 359 Going Hard [R-18]

The only way to stop the earth’s doom.Is to seduce the girl who is the student council president.

The story is about a man who’s opposed to the now-common practice of implanting false memories, but is one day given memories of a fictional childhood friend. This fabricated happiness torments him, but then, to his surprise, he meets her – a girl who shouldn’t exist.

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.

Mortimer Zhu is an extremely unfortunate high school student who accidentally enrolls into an academy of a dubious nature, where it is the norm to jump in front of moving trains, get dismembered during orientation, and crushed by vindictive bouncing classrooms. Can he stay alive or will he die from the rigors of school? Why have evil spirits suddenly acquired a taste for his flesh?

- Description from Novelupdates