Supreme Harem God System - Chapter 1631 I am much stronger than whatever you are thinking.

She was bored, so the Emperor accompanied her as she played in the three thousand realms and caught a phoenix for her to sit on. When she has cravings, the Emperor crossed through space to gather all kinds of delicacies and immortal fruits for her. Later on, she liked little kids, the Emperor tricked her, saying if she becomes the Empress, she’ll get her own kid. And like that, she became the Empress and got tricked by the Emperor into bed. However, she reincarnated and forgot everything…..

- 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.

A global game, starting with inheriting the legacy of super god-level civilization, a universe in the palm of your hand!

If you feel the seedlings of this book, there are thousands of people who have ordered this old book (the era of global gods) and send it over by clicking on the author’s name.

- Description from novelbuddy

The consciousness of a Great Magus suddenly returned to his original body on earth, just before he transmigrated into the magic world.

Nothing has changed, it's still the same earth.

However, when he looked at earth once more as a former great magus, he discovered earth was not as simple as he knew it to be.

Hidden magus, legendary races such as vampires and werewolves, they do exist, ruling the world through the shadows.

Faced with a former great magus, who possessed as many spells as libraries, would the earth that had been ruled by a few people be able to remain calm?