Author Of Worlds: I Reincarnated Into My Novel As A Random Character - Chapter 7: We Have To Make A Sacrifice To Stop The Fused Shadow...

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.

It began with an accident, or maybe a miracle is a better term. Three souls dying by different strokes. One died in glory and blood; One died, betrayed but glad it was over; One died poor and alone. Then on the child’s fifth birthday, the three sleeping souls awakened. Three souls, one body, two desires, and containing all the powers each had in their last life. Were they destined for greatness? No. But when the past comes to haunt them, their home taken away, they have to make a decision… May it be as simple as a majority vote.“Let’s squash them!”“...can we just run away?“Were you never taught to aim for the eyes?”

Before the rebirth, Gu Qingyao wanted to marry him but did not dare to marry. After the rebirth, Gu Qingyao, with the space materials in hand, all day planning to marry him with a huge dowry.