Rebirth: The Fake Young Lady Is A Real Young Lady - Chapter 25

The villainous young master Dark Demon finally recalled the memories of his previous life at the sorting ceremony of the Dueling Academy. He was reborn in a very strange Galgame world.

And he was the ultimate villain in the game, the Demon God of Seven Original Sins!

Superbia、Invidia、Ira、Accidia、Avaritia、Gula、Luxuria！

Once any one of these seven indicators broke through the critical value, he would irreversibly transform into the Demon God!

In the era of Saint Marian, where the demons had been completely destroyed and the demon king had fallen into eternal sleep, no heresy was allowed to survive!

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.

Untolerated by heaven, a boy was restricted by the most powerful spell.