The Ice Lord Prime Minister's Black-Bellied Wife - Chapter 40

After coming out of a tunnel… it was pitch dark.

The Demon Empire in the universe was reborn and came back! Enemies should kneel down in front of him! Beauties should lie down in front of him!

“I am a demon. I enslave gods and immortals! If you don’t succumb to me, I will convince you by force!”–Ye Feng!

- 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.

Can you get used to dying? Not really.

When a particular universe was born, its seven primordial Concepts acquired an ego. Omniscient and omnipotent, they seek since to enrich their home. To do so, they plunder other universes, capture young civilizations and plagiarize ideas. Many monsters, gods, civilizations, and races are competing for the eighth throne.

Eons later, it is Earth's turn to be torn away from its Sun.

Humanity begins its integration by participating in a Tutorial. Priam has the luck and the misfortune to finish the Tutorial first. Luck because his reward is a form of pseudo-immortality. Misfortune, because as the champion of his civilization, he is transported to Elysium, the most dangerous world created by the Concepts. Nine out of ten champions lose their lives there on their first day. Fortunately for Priam, he has many lives.