Cultivation Nerd - Chapter 27: Experiment #1

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 Emperor had issued an official decree to appoint a successor to the throne—one who would become the next ruler of the empire.But instead of a direct appointment, the successor would be determined through a formal battle among the princes and princesses.A battle that would drag in many factions, overflow with conspiracies, claim countless lives, and reshape the entire continent... was about to begin.But among the contenders, there was one prince who had no intention of fighting—Nolan.Handsome, lazy, and utterly annoying, Nolan was well-known for the many unflattering titles given to him by those around him.Nolan: “Fighting to become emperor? Please... I just want to relax and enjoy life.”Rather than compete, he convinced his twin sister to fight in his place while he supported her from behind the scenes.Nolan: “My dear sister, I leave my future in your capable hands!”And with that, the prince’s journey toward a life of leisure—relying entirely on his sister—officially began.

You take up a student career.

Student career upgrade to lv.7

Acquired skills: primary school knowledge, junior high school knowledge, high school knowledge.

You take the college entrance examination,

You got a perfect score.

Your basic occupation has been upgraded to lv.9, and the job transfer system has been activated.

You change jobs to become a scientist, you gain R&D skills

You use research and development skills to get space fortress construction technology

You use R&D skills to gain starship technology.

You are invincible.

- Description from novelbuddy

Lambert, one of the great generals from Regios kingdom was suspected for planning a rebellion against his lord at the end of unification war, he died an unnatural death. Two hundreds years later, when the era has changed and Regios kingdom entered it’s peaceful era, he accidentally revived as a demon called Undead Knight.. Lambert whose entire body was wrapped in a flashy Demon Metal[Organ] set out on a journey to punish the wrongdoers while enjoying the peaceful sight of Regios kingdom. But…….. This peaceful era was basically an easy mode for Lambert, the greatest general of the chaotic era.