Abandoned by my Childhood Friend, I Became a War Hero - Chapter 80: -The Grandmaster

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.

When the last prodigy level esper on Earth disappeared, Earth was in deep trouble of becoming another species’ colony. The ordinary Han, with his intelligence and hardworking character, was able to make a fortune after “accidentally” stepping into the world of dark net, later purchasing an esper power crystal that brought him the ultimate power that changed the fate of the universe.

Her – a glutton without troubles or worries who crossed over and became a young fat chick with a deep vengefulness.

Him – a young master of the number one power; a two-faced man with elegance and charming, good looks; he is the chosen one of the former saint god and a man who will only bend his back for her alone.

This domineering crossover’s slogan is, ‘Don’t touch if it is this sister’s, put it there if it isn’t this sister’s!’

…watch how the Domineering Glutton and the Two-Faced Venerate Emperor create sparks as they meet and collide, stirring the whole Spirit Treasure Continent into turmoil, how they fall for each other and how they kill each other, how life and death severs love.

- Description from Novelupdates

war, blood, and betrayal carved him into something else. A legend. A killer. A mercenary whose name struck fear into both criminals and so-called heroes alike.But now, the world had changed. Lines blurred between right and wrong, between justice and vengeance. Should he step into the light, wear the mask of a hero, and fight for a cause greater than himself? Or should he embrace the darkness that had always been his home, a place where morality was just another illusion?“Don’t box me in with your shallow ideas of good and evil,” he muttered, his voice calm but edged with danger. “I do what I want, when I want.”The air was thick with tension as he moved like a shadow through the dimly lit room. The writer had no time to react—one moment, he was scribbling nonsense about legends and myths; the next, a cold barrel pressed against the back of his head.The figure smirked beneath his mask, eyes gleaming with something between amusement and menace.“You wanna write fiction?” he whispered. “Then let me show you how real legends are made.”A single gunshot shattered the silence.As the writer’s body slumped over the desk, the man holstered his weapon, stepping into the faint glow of a flickering neon light.“It’s that simple,” he said, his voice unwavering. “I’m Deathstroke.”