Riaru de Reberu Age Shitara Hobo Chītona Jinsei ni Natta - Chapter 7: Transparent Conversational Space

She is a descendant of Shennong with unparalleled medical skills and possesses a unique treasure. He is a handsome warlord who mysteriously goes blind and is sly and cunning. Crossing into another world, she becomes a six-year-old little waste. Through defying the heavens with summons and forbidden magic, she rises up in one fell swoop, showing a dazzling brilliance, looking down upon the powerful.When arrogant meets cunning and genius clashes with monstrosity, at that moment, the world trembles in awe!

CEO Leng Li: The sky has finally cooled down. It’s time for that person who bullied my sister to go bankrupt.

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Jie Ao –xianzun (officer of Emperor Jie): The emperor is not allowing me to marry my junior sister? Good! Then, both of us are going to elope.

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Overbearing Regent: This is my little princess! What do you mean by thousand pounds of gold and precious nobles? All of you kneel down to her!

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Tong Su only wanted to complete her task of eradicating the scum male in order to get a chance to exact her own vengeance. However, this big BOSS, why do your eyes show such emotion towards me?

Important note: Sweet pet, oppressive slag, fake brother and sister, not blood related!

- Description from Novelupdates

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 rivers and lakes carry wine with swords, the waist is slender and the palm is light.

The young man carried a long knife on his shoulder, and hung wine on his waist, striding forward, but the rivers and lakes in his heart were vaguely visible.

Turning a page in the book of troubled times, the rivers and lakes have been raining nightly for decades.

Looking back suddenly, the world has been shattered.

- Description from novelbuddy