Youkoso Jitsuryoku Shijou Shugi no Kyoushitsu e - Volume 13, Chapter 1: School life is changing Part 4

Just like how everyone adored heroes in their childhood, a certain young man adored those powers hidden in shadows. After hiding his strength and living the mediocre life of a mob character by day while undergoing frenzied training by night, he finally reincarnates into a different world and gains ultimate power. The young man who is only playing at being a power in the shadows, his misunderstanding subordinates, and a giant organization in the shadows that gets trampled…. This is the story of a young boy who had adored powers in shadows possibly eventually reigning over the world of shadows in another world.

When people pass away, they often leave behind unfulfilled wishes. I will act as a force of justice, helping the deceased achieve their final desires before I return to my own world to confront and make peace with my own regrets.

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.

The female soldier king traverses into a useless little girl, confronting the strongest ghost lord who is both salty and sweet.She is the first legendary female soldier king in history, who traversed and was actually sold by a scumbag!!Unable to cultivate, abandoned, and cursed for a hundred lives, without a good ending?She holds a book defying fate, enslaving the heavens, making the earth her servant. Whoever splashes dirty water on her, she boils it and splashes it back.Punching scumbags, kicking white lotuses, with the universe in her left hand and the world in her right, she counterattacks in one fell swoop, changing the winds and clouds.Behind her, a lazy voice calls out.“Stop right there. I've confirmed through the eyes, you are the woman this lord wants to flirt with.”