A Star Reborn: The Queen’s Return - Chapter 81: The Vow Meant Nothing More

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.

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of power enemies depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest!

Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.

- Description from Novelupdates

Lucas is a homeless teenager who had everything taken away from him— his family, his home, his childhood. Even worse, he was born without any abilities in a world where humans with superpowers dominate.

All of that would change when a new dungeon appears before Lucas.

Thinking that it was a sign the gods have given him— that he should just give up and end himself, Lucas enters this dungeon without hesitation while expecting death.

However, inside the dungeon was not the end like Lucas had expected.

Instead, it was the beginning of his life of carnage.

Wielding the power of a «Hero», Lucas begins his journey of vengeance on the world that stole everything from him.

The world is filled with talented people. But, there are many who never possessed that talent. They work hard, but hard work often doesn't give them a good result.

Fu Chen was one of those. He was a mortal, without any talent for cultivation. But, with the help of an strange encounter, he inherited the Strongest Offline Cultivation.

Join Fu Chen's journey where he uses his system, not to be strong but to gain talent. Because he knows the power doesn't come without the sacrifice, so he isn't willing to use his system to gain strength.

Rather, it opened a path for him. A path where he encounters opportunities which he couldn't even dream off before.

Traveling in this path, he finally gets a chance to accomplish his dream but accomplishing his dream was just a part of a bigger goal. It was the mystery behind his system.

Where did it come from? Was he alone? Are there other people with such systems? All of these questions began to pop up in his head and he knows he must find the answers.