I'm The Devil - Chapter 15: Mysteries

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.

All of a sudden, various watches appeared out of nowhere in different parts of the world. These locations were quickly controlled by various organizations, and then the marketing of the watches was strictly controlled.Why was this? Because these watches gave access to a unique world: Eternity!Eternity functioned more or less like an open-world game with a single-player mode, except that Eternity was a game where you could actually die!By joining Eternity, everyone awakened a unique talent.This talent helped unlock the first classes, which allowed you to strengthen your physique both in Eternity and in the real world!Not to mention the various skills and talents available...And above all, there was the legend that it was possible to become immortal thanks to Eternity!It was with the aim of changing his destiny that Maxime trained his whole life in swordplay, and for many years saved his meagre salary to obtain one of these famous watches!Watch his rise in the real world thanks to Eternity!

With the revival of spiritual energy and the breakdown of the order of species, it is a difficult test whether human beings can still stand at the top of the biological chain.

(There is already an old book, The Strongest Descends in the City, you can read it.)

- Description from novelbuddy

The emotionless Young Master Bo had finally gotten married. Rumor had it that the new Mrs. Bo was easily jealous and had set a family rule on their wedding night: Her husband was to return home every night, and no other females could be around him! Gradually, everyone in Jiang City realized that Young Master Bo's wife was a tigress!On their wedding anniversary, Young Master Bo brought his wife along for an event. Mrs. Bo was young, pretty, and delicate. Every time her eyes lingered at any man a second longer, her husband wouldn’t hesitate to destroy that man's company!Faced with everyone’s gazes, Mrs. Bo couldn’t help but decry, “Bo Jingyan, you've been ruining my reputation again!”Young Master Bo simply coaxed her solemnly. “You don’t know how fierce other women can be! Baby, you must protect me.”Mrs. Bo couldn’t help but flare up. In truth, he was the one who exerted strict control over her in private!