Alpha Razor King - Chapter 104: Unusual Visit.

The protagonist transmigrates into a novel and gains a system where they grow stronger by simply writing in a diary.July 7th, sunny: “The boss’s outfit is hideous again. Wouldn’t it be better to wear something cooler?”July 7th, evening: “I’m about to have my engagement called off. So excited! How should I act?”July 7th, evening: “Lin Qingyue, the female lead, is probably going to drown her sorrows in alcohol.”The protagonist thought it would be easy—just jot down daily musings, record life’s events, and earn rewards. All while playing the part of a villainous, bootlicking second-generation rich kid, moving along with the original plot.But unexpectedly, the female leads gain access to copies of the diary entries.One by one, they stop following the script, and the plot spirals completely out of control.July 10th: “The female boss is an idiot—no one would want her.”Soon after, the protagonist gets punished at work, all because they entered the office with their left foot first.

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.

He swore that if he was given a second chance to live, he would live his life to the fullest.His life was full of misery but he was reincarnated in the body of the son of the strongest expert in the empire.He had the looks, wealth, and women. He was known as the “Handsome Playboy” and he didn't want to become a righteous protagonist.He awakened a system that can make him strong by making others feel the 7 sins towards him.He will collect many beauties and live to the peak of life.

Jiang Chen accidentally traveled through and started his comprehensive journey.

The world is tentatively scheduled: Naruto – Attack on Titan – Blade of Demon Slayer – Sword Art Online – Detective Conan, etc.

————

In the Naruto world, Jiang Chen obtained the apprenticeship ten thousand times return system, as long as he taught his apprentices, he could get a correspondingly high return reward.

As a reward, Jiang Chen taught Hinata the black coffin he brought from the world of the god of death to Hinata.

During the Chunin Exam,

Neji: “Abstain, Hinata, you are not fit to be a ninja.”

Hinata: “I don’t want to run away, Brother Neji, let’s have a showdown! The turbid coat of arms is faintly revealing, and the unruly and arrogant talent… The Ninety of Destruction: The Black Coffin!! !”

Everyone: “You call your brother on the lips, but you actually kill him. This girl is too scary!”

(The introduction is weak, please move to the text~)

- Description from novelbuddy