Academy's Silver Gatekeeper - Chapter 155

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.

Xu Jiayan is sick, suffering from a condition where he can't stand to see Jiang Yuan cry. Whenever the young girl sheds tears, he just can't help but feel weak in the knees.However, one day, after accidentally catching a glimpse of her slender waist, he feels his condition has worsened.He finds himself wanting to make her cry,yet he has no desire to seek a cure—How fatal!One-liner:A pseudo-sweetheart vs. a true scholar;Childhood friends turn lovers with a twist of love and war;From school uniforms to wedding gowns, only accompanying you.

At her cousin's birthday party, she was schemed to have a relationship with her cousin's fiancé, becoming the most shameless woman among rich families, and therefore married to that man, the most influential big shot in the city.After marriage, the wholehearted love only brings endless humiliation and disgust.Later, her cousin returned. He threw out the divorce agreement, saying, “Give Mrs. Leng's position back to her.” He even took their child and gave it to her cousion who was unable to bear children.She finally became disheartened and fled far away with their child, completely disappearing from his world.On his wedding day, he suddenly learned the truth and realized that his white moonlight had always been her, not her cousin.“If love is an isolated island, I'm willing to settle there for you forever.”

An ordinary student accidentally traveled into an other universe and became the king of a small kingdom. He had gotten a “Cheating Code” of life and was able to complete something extraordinary. This is the story about a king that was able to conquer continents and leave behind him an ultimate legend that will be recited between every generation to come.

- Description from novelupdates