The Black Beast’s Useless Concubine - Chapter 2527

While on a school field trip in the Czech Republic, Kang Hyuk happens to stumble into a shop called “Archmage.” To his disbelief, the shop is actually owned by an archmage… from another world! Forced to become the Archmage’s disciple, Kang Hyuk is punted into the Kallian Continent, where might and magic overwhelm and wyverns fly high in the sky…

In this world, people are either sword-wielding knights, magic-wielding mages, or spirit-wielding summoners. There hasn’t been anyone yet who can do all three… until now.

In the early morning of September 23, 2019, a natural disaster arrived. The Dao of Heaven and Earth has changed, the desire of all souls have completely filled up the Heavens.

The Dao of Heaven can no longer bear it. Evil thoughts, good thoughts, obsessions, and desires entangled endlessly, making the Heavens reach its limit, this shift caused an extreme change in the world, making fantasy come to reality.

All worlds fused together, and all things compete for freedom in this cruel new world. This is the beginning of a new era, one filled with destruction and rebirth. This era is called the Eternal Era.

- Description from Novelupdates

The plague of insects descended overnight. As an ordinary person without invincible powers and extraordinary exercises, facing blood and death, what should we do at the critical moment of life and death?

(I am a reasonable party, but the novel needs appropriate YY, please do not excessively investigate the rationality of the background in a razor-sharp way.)

- 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.