Warrior’s Promise - Chapter 3264

Raised by a league of assassins and trained for thirteen years, Shan Yue was seventeen when she took the throne of best assassin, becoming an untouchable legend amongst assassins.

Despite being legendary, she put her faith in the wrong people and was killed by her own league’s betrayal. However, while Shan Yue thought her death was assured in the violent explosion, she was surprised to find herself reincarnating into the body of a useless female student.

Forget how pudgy and dim-witted she was — she seemed to get into fights every day! Her original body’s sister sneered, “Fatso! All you do is eat… and look at how ugly you are! You really embarrass me!”

Fat? Ugly! Shan Yue started a daily training regiment, rapidly slimming down and becoming a ravishing beauty! Her original body’s mother snapped at her, “How did I give birth to a child as stupid as you?! Always last place in school — you embarrass me!

I should have strangled you right after I gave birth to you!” Stupid?

Last place in school? Shan Yue lifted a finger, and the principal of the top school in the capital personally visited, offering a transfer to his school. Elite hackers, doctors, mercenaries, math geniuses…

All of them were now vying for her attention! Though she managed to get the chance to become normal after going through so much, she accidentally become a big shot again, even finding herself a two-faced bigwig for a husband! Shan Yue: I just wanted a quiet life, but my abilities prevent that. Sigh…

Arakawa Kouki is reincarnated to a Japan with a different history than the Japan he knows with the memories of his previous life still intact. Kouki was discouraged, “Aren’t reincarnation stories supposed to be at some fantasy world filled with swords, magic and elves?!”

In the Sky Sword Continent there are thousands of sects and strong cultivators as common as trees. In order to prevent his older sister from being forcefully married off, Lu Xuan had no choice to but to unceasingly cultivate and enter a sect to ask for a favor. By chance, a sword-shaped crystal of mysterious origins entered into Lu Xuan’s body, containing countless top-class martial skills, powerful martial arts, and everything you could wish for! A martial legend starts here…

- 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.