Aether Beasts - Chapter 252

The most precious things in the world are priceless. Ordinary men tend to turn a blind eye to this fact. Apart from the treasured air, sunlight, and familial love, there is still one more thing that’s extremely valuable. It’s right beside you and can be easily obtained.

- 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.

Apollo Kaiser, a boy who bore the unlucky fate of being unable to grow strong, was condemned by his family.

Discarded by his mother and abused by others, Apollo gives in to his rage.

However, this action results in his death. Many would believe it to be the end, but Apollo's death was a required catalyst.

The Demon Monarch System finds its heir and attaches to his soul, bringing him to a new world where he starts his journey to supremacy.

This difficult journey rife with conflict, conquest, and brutality shall serve as Apollo's temperance.

Watch as the heir of the Demon Monarch rises above all, conquers Sin, subjugates unthinkable enemies, and even brings about the destruction of worlds!

The rise of the next Demon Monarch begins...

“Married rich for three years with no child born. Just when she was finally cured of infertility and ready to give him a child, he brought home his pregnant mistress in high profile.