MTL - Rebirth: Noble Woman, Poisonous Concubine - Chapter 84 , Wolf den

One day, a villainess came to the orphanage.“I absolutely can’t stand children!”“How can someone my age have a child? It doesn’t make sense!”“What’s so great about these little creatures that tire you out all day long…”Setting aside her dislike for children…Somehow, after she arrived, the children started gaining weight.“It’s all because of the contract, you know?”That’s what she says.While personally feeding them sweets she made herself.

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.

Being a nobody from a poor district of the Federation, Nick is a sixteen year old boy just trying to find his place in the world. When he finally gets his shot to enter the Beast Domain upon turning sixteen, he jumps at the opportunity to finally make something of himself — to carve out his own future.His goal? Survive. Hunt. Earn enough money to finally support his little sister back home and bring them out of poverty.But to a naïve young boy like Nick, the world is far more sinister than it seems — leaving him no choice but to adapt or die.To a poor young man like Nick, though, there was only one choice he could make.Follow Nick as he navigates these obstacles and carves out a future for himself and his sister, all while uncovering the various mysteries that shroud his worldview in darkness.

Apocalypse befell, and roommates performed a skyward ritual.As the fog descended, the Book of Blood Spirit appeared in the hands of all survivors, and only those with a Contract monster could survive.Su Han directed his gaze to the neighbor who had already mutated and twisted, silently pulling out a gleaming fruit knife...Grotesque meat corpses, giant spiders with gaping mouths, eyeballs enveloping the city, one-eyed sharp-toothed hand monsters...Civilization fell, cities shattered, and all humans became meat for the monsters. There was only one way to survive:Use monsters to fight monsters.