Naruto: The Hidden Protector - Chapter 23: It’s time for your teacher to keep her part of the promise

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.

I became a side-character who died in anguish because of her good-for-nothing husband.

If I can’t avoid getting married, why don’t I change who I marry instead?

“Excellent, marriage sounds good.”

“Wise choice. Then let’s have a wedding ceremony that isn’t too ceremonious. Following that, I’ll need you to go down to the Fief and behave like the lady of the house until I call for you. Naturally, there won’t be any time to spend in leisure whilst dousing yourself in luxuries.”

“I’m not marrying you, but your father instead.”

“……Pardon?”

“I’m not going to marry you. Do you have a problem with that?”

“I'm a monster? Why is every player I see trying to kill me?”------------Kai, a young man paralyzed by an incurable disease, decides to play the new VRMMORPG called Realms of Monsters in search of freedom and adventure. However, when he logs in for the first time, something unexpected happens.While everyone else chooses their class and race, Kai awakens in the middle of a forest... as a salamander.Luckily for him, he won't stay a salamander for long.[Mythical Evolution System activated.][Devour a monster to evolve.]Trapped in a monstrous form, Kai must navigate a hostile world where every player is a potential enemy. With the Mythical Evolution System, his survival hinges on his ability to evolve and grow stronger. In a game where everyone else is a hunter, can Kai rise from being the hunted to becoming the ultimate predator?

I, Zhang San, am absolutely a good person!I swear by the eight generations of my ancestors!What!? My ancestral grave just exploded!?