Level 4 Human in a Ruined World - Chapter 416

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.

Let her shout out: “Oh handsome and sweet-talking Tokyo gentleman, I must have you. You are mine!”This is the story of how a boy from Iwate Prefecture became a Tokyo gentleman.

In the Dragon Abyss Empire, nestled within Clear Water Town, young Jiaang Lin awakens from a brutal beating by his cousin Jiaang Ren, only to discover he has been reborn into his younger self. Once a mocked disciple with blocked meridians, Jiaang Lin had risen to greatness in his past life as a prodigious warrior and Pill Saint. Now, with a second chance, he vows to protect his loved ones and conquer his enemies. How will Jiaang Lin change his destiny and ascend to the pinnacle of martial prowess once more?

Q: How would you approach your target?

Tiger Tribe:
Jiang Yu (excited): “Cure him, give him medicine!”

Future Mecha:
Duan Jingzhe (at a loss): “… umm … feed him expired nutrients?”

Ancient Court:
Donghao Yang (banter): “Follow nature’s example and flirt shamelessly.”

Next unlucky protagonist: “…”

This is a collection of three short stories in which each protagonist crosses to another world or is reborn.

- Description from Novelupdates