Married To The Last Ice Dragon - Chapter 10: Why can’t you die?

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.

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure–-did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the nation! What’s more, he’s betrothed to the king’s daughter now…?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side. Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess…?! What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!

One day, Yoichi who grew up while not knowing his parents has received the news of his father’s death. His father left behind a testament——which said he is to pick only one out of five ‘little sister candidates’?!

The Red Dragon came from the vast wild wastes, coveting all the strength in the world. It once had countless titles: Mountain's Wrathful Flame, Infernal Calamity, Crimson Emperor, Ashen Dragon......The world trembled under the shadow of the giant dragons. He stirred up the craze of the magic industrial revolution; in the empire he established, Wyverns roared, artillery fired in unison, and steel beasts appeared in the sky and on the land, while disasters from another world rampaged everywhere.“Submit, or die.”Cassius spread his wings, blotting out the sun, and gazed down at the trembling humans, elves, and dwarves below, saying thus.......It is a story about a Red Dragon with a player template conquering, ruling, and transforming an alternate world.(Pseudo of DnD, The Fourth Calamity, Red Dragon)