MTL - Wild Malicious Consort: Good For Nothing Ninth Miss - Chapter 2066 Sincerely

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 weary historian dies and finds himself in a different world awakened in a life as the notorious young Duke of a southern state. His nation is weakened, his army underfed, and his neighbors revolve around his lands menacingly. No one believes his land is going to hold out until winter.But this newfound duke is no naive simpleton his enemies recollect. He carries with him the experience of centuries of war and empire, of starting and ending monarchies. From Caesar to Napoleon, from the Mongols to world wars, he has learned from each of them—and his strategy is to make history his very own arms.He organizes his smashed levies into well-trained formations, rebuilds his castles, and turns his villages into supply centers. Where others see defeat, he senses opportunity. As he triumphs, rumors spread: of a pennant red as winter snow that shall not go to ground, of a bloody duke who writes his name in gore and flame.Is he a savior who's constructing a new empire, or a tyrant who's going to bring the world to endless war?

Have you ever thought about how your life would turn out at the age of 18?Well before I could even say that I was an adult to even say I was going to conquer it.The world had seemed to already be determined of what mine and the rest of humanity would be when the first Leviathans was made public to our world.

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)