Reincarnated as a dragon’s egg ～Lets aim to be the strongest～ - Chapter 20

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.

Quinn Winter is a young man from another world. One day, he is suddenly chosen to become the new Demon King. But the Demon Kingdom is in big trouble – it's losing a terrible war against the human kingdom called Gran'le.To help his people, Quinn comes up with a risky plan. He will sneak into Gran'le and learn their secrets. But things don’t go as planned. A powerful noble sponsors him, and he ends up joining Heavenward Academy, the top school for training future heroes.At the Academy, there's a big challenge called the Selection. The best students become Paladins – magic knights who fight demons. Quinn doesn’t want to become a Paladin. He is a demon king! But now, he’s stuck in the Selection… and if he wins, he’ll become the very thing he’s supposed to destroy.He started the day badly. Now, things are getting even worse.

“Brother, I loved you since before I was born!”

Corporate s*ave Yukimura Rina was reincarnated as the villainess Ekaterina from an Otome game. In her past life, she was obsessed with the brother of the Villainess, Alexei, but seeing him in real life is so much better than in the game! It’s just that, her brother’s upbringing is just so sad that she cries every time she thinks about it!

“Okay! I’m going to escape mine and my country’s destruction flag and make sure everyone lives happily!”

Thus, the villainess from the prestigious 400-year-old Yurinova Dukedom along with her sharp-tongued tendencies back when she was a corporate s*ave forge on forward. With her common sense and knowledge of history, she plans on saving her brother and overcoming all the game events.

For some reason, as time goes by, her talented brother becomes more and more of a siscon. Wait no, he was a siscon to begin with, but she’s more than happy to spend more time with her brother as a brocon and siscon.

And as time goes by, her plan to avoid the heroine and the prince death flag has become more and more messed up. Why? No no, the two of them are good people and good friends, but…

“Prince, stay far far away from me.”

Even so, the settings of the Otome game she played before are completely messed up in this world, nothing is the same.

Anyways! The evil villainess Ekaterina will do her best for the sake of her brother!

Living things really are ignorant – the greed to obtain the key to knowledge and the fundamentals of energy overpowers them. Little do they know that knowledge is full of lies and energy is the root of destruction. Us, mages, have mastered travelling through space and time. We are invincible, we can turn worlds into dust and you, mere ants, will be wiped out with no trace.

-Mage Adam

An A.I.(Artificial Intelligence) gets reincarnated into a world where he becomes a mage.