Kill the Lights - Chapter 15.3

When Orion is mysteriously transmigrated into a primitive world where sex and other goods and services can be bartered for, he is determined to make the most of his second chance at life.

But as he delves deeper into this dangerous world filled with temptation and magic, Orion must use his wit, charm, and thirst for adventure to survive and make the most of his second chance at life.

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.

Ye Song, who once lived in a technologically-advanced world, died and reincarnated into a noble teenager’s body in another world.

A fantasy world filled with magic!

A series of events filled with tragedy, action, etc. began to unfold one after the other when he fatefully encountered one of the most guarded secrets of this world, obtaining the legendary power of Wizards.

Watch how he reaches unreachable heights as a powerful Wizard in this new world.

- Description from Novelupdates

“You’re pregnant, young master.”Valentin Wiche, the beloved only son of the Viscount Wiche family. One day, he realizes that he has been reincarnated as the villainous supporting character in a novel he read in his previous life. To avoid his miserable fate, Valentin seduces an alpha at a ball.“Your scent is truly dizzying…”Did that alpha enjoy their night together that much? He starts showing tremendous obsession.‘Where did this come from?’‘I must have this.’He only did it to avoid the terrible ending of the original story, but the result is pregnancy? Moreover, the identity of the child’s father was someone even more incredible than he thought – Reynard Dennox, the only heir to the notorious Dennox ducal family and a naval hero of the Heston Empire.On top of that, true to his reputation as a klutz, Valentin’s pregnancy is immediately discovered….“Why the sudden ring…?”“What do you mean why? We even have a child on the way, so we need to get married quickly.”