Valkyrie's Shadow - Chapter 11Winter’s Crown: Act 3,

It took a long time for Yu Qingjia to learn that she was the original heroine in a Mary Sue Novel, and the other party held the female supporting system in their hands, and She was gearing up to grab her opportunity.

Hehe…

Anyway, sooner or later, she’s going to die, so it’s better to live a more comfortable life. Yu Qingjia completely let herself go, relying on her status as a legitimate daughter, she played her life against her father’s new beautiful concubine. This little concubine is not a good stubble either, as they come and go, the relationship between the two of them becomes bigger and bigger. Later, she gradually realized that something was wrong.

Why is her formidable enemy a ‘man’?

He is also a wanted man of the royal family, the youngest son of the deposed prince, and a famous tyrant in the future!

The royal family of this dynasty has a secret. For example, although these royal men are all beautiful and good at fighting, they are bloodthirsty, paranoid, and cruel from their genes.

Murong Yan fell from the clouds into the dust when he was young, and even had to disguise himself as a woman to avoid spies in the backyard of his followers. After great changes, the tyrannical element in his body could hardly be controlled until he met Yu Qingjia, his nominal “daughter”. In his restless and dark world, the sun suddenly radiated in.

- Description from Novelupdates

The sky thunders, Fang Yue, the nail household, dies on the street, the heavenly court blackmails, obtains compensation, reincarnates, and sees how Fang Da Devil disturbs the universe and upset the world.

- Description from MTL

Scheming female assassin transmigrated to become the weak Eldest Miss, her story is wonderful and stunning, attracting peach flowers to blossom open. Cold calculating emperor? Genius bad crown prince? Insidious happy-go-lucky prince? Gentle physician? Ice-cold mystery male? Who is her true love? Haha, but she only eats, definitely will not take responsibility! Beautiful men be careful!

- 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.