Valkyrie's Shadow - Chapter 4Before the Storm: Act 8,

After an ultimate battle against the King of Hell Lucifer, Asmodeus, the Vampire Emperor, has fallen. Although he lost, he died without regrets and with a smile, prideful that he had managed to corner the King of Hell himself to such an extent.

However, due to a sick twist of fate, Lucifer himself decided to reincarnate him into the feeble body of a human child named Blake, desiring a rematch in the future!

Now, given a new opportunity at life, Blake will use every possible way to grow stronger and protect his new family in a turbulent world where people can summon spirits to fight and develop their magical powers.

Armed with only a Grimoire, he’ll slowly summon all of his previous life subordinates, who are all powerful Vampires, and rise to the top while fighting the ever-growing menace of the Demon Towers.

Accompany Blake through a journey filled with excitement and growth and experience the rise of the Vampire Emperor. A new Era of Blood is about to begin.

In the twenty-ninth year of the First Emperor, Bo Langsha was attacked.

When Ying Zheng merged the memories of the 21st century history doctor, looked at the mighty mountains and rivers in front of him, and said to himself, “In this life, my Daqin can’t die!”

- Description from novelbuddy

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.

Night City, it’s a place of endless wonders and horrors. Opportunities and dangers, but before Motoko Kusanagi can access any of them. She first has to build up enough strength to walk again. Learn the basics of living in a world that was just a game to her before. Good thing she found a Shard hidden in her stuff that opens the door of opportunity. But like all opportunities in Night City, it usually ends up in a gunfight. Self-Insert with a modified Cyberpunk 2077 Gamer System. Not a direct Ghost in the Shell Crossover. MC just happens to share the name.