Super Necromancer System - Chapter 19: Valera

Zhuo Yifan was the Demon Emperor. One day, he managed to lay his hands on an ancient emperor’s book, the Nine Serenities Secret Records. As the book was coveted by many, he was targeted by experts and was even betrayed by his student.

In a romance novel called “The Secret Lovers of the Academy” the male lead would often torment his fiancée–but wait, why did she cross into this world to become his fiancée, the villainess, instead of the heroine?

Louise Sweeney found the perfect solution to escape the misfortune of being the villainess: “Your Highness, I just want to tell you that we don’t have to be tied with our engagement. We weren’t even officially engaged, right?”

But what was wrong with the male lead’s reaction? To her suggestion, he replied “But our engagement wasn’t false, don’t you agree?”

Neptune in One Piece, Tail Beast in Naruto, Fate’s Fantasy Species, Gourmet Captive Cuisine.
This is a dimension restaurant opened in Marvel, connected to dimension world, welcome you to taste the deliciousness of world.

- Description from Uukanshu

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.