Reincarnated as the Villainess's Unlucky Bodyguard - Chapter 68: No Time for Regrets

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.

“After every fire, ants survive.”

…

Mysterious anomalous biological metals have polluted the world, and the world has undergone tremendous changes. Metal sickness is like a key that opens the door to evolution. Under the tide of evolution, there are no innocents.

The choice is up to you, do you want to be the surviving ants after the fire, or do you want to risk your life, step on the glorious long steps to the gods, and glimpse the supreme glory of the mother goddess?

…

Touch the totem in your heart, follow the inspiration, and step on the long steps of ascending to God:

[Amphibians] → [Atlantic Glory] → [Ningen]…

[Eight Arms] → [Nightmare in the Sea] → [Deep Divers]…

[Eagle Eye] → [Owl Ghost of the Night] → [Jersey Demon]…

[Living Dead] → [Grave Digger] → [Death Ferryman]…

…

“On that day, the world was polluted, and I was the source of pollution. Human desires are endless, desire is the best food on the way to evolution, and I am the embodiment of desire.”

– Joe Tour.

- Description from novelbuddy

Zack “Kazz” Foreman once was a human from the earth when humans went through a dramatic change because of an event. This forced them to evolve into energy-based beings but was sucked into another dimension.

Forced to start living out lives on random worlds in a fractured dimension, Humanity is placed on the path of complete extinction.

This is controlled by a demon king at a place called The Center of Everything.

The Demons try to force Humanity's mark from every reality, so there are only demons, but the Demon King feeds from anger and pain. A constant tournament going at the center of everything to feed his hunger.

Kazz made it to that point once, but was tricked, refused entry to the tournament because he had offed a place one of the gods of the worlds.

Refusing to give up, Kazz goes back to the beginning to start again. To do this, Kazz must give up all of his memories to choke the flow of demons born fully grown from a pool of recycled souls.

This journey starts after he lives a solitary life trying to get stronger but not knowing why. The world Kazz is on is like our earth, but it was only a mimic of the earth we know.

Caught using steroids and about to give up and join the army, Kazz stumbles onto a cave in the ground. He is transported to a world filled with demons and monsters, and a human god named Hero is speaking in his head.

Hero, a person Kazz knew but was not friends with, followed him to help but was lost from him. Upon meeting Kazz, Hero offers him the Hero System to help him advance in this new world.

Kazz refuses after trying to get to the top and failing to use the easy route. This starts a series of frustrating events for both Heroes, but they learn to work as a team over time.

Kazz will meet misbegotten monster girls and demons that he agrees to take care of in this world, using the Ranching System. It only gives bonuses to the girls and skills to help raise them, but he will also learn to control the Elements with Shamanic abilities.

Son of the Senior Chancellor, Luo Wei, loved the wrong person in his past life. This mistake caused his entire family to be wiped out, and in the end, he was cast down as a pleasure slave, and died in the wilderness during the depths of winter.

Somehow, the heavens did not give up on him and gave him a second chance at life. He believed this rebirth was only meant for atonement, and not love. Yet, as he plotted his vengeance, Luo Wei quickly realized that passion would again be his fatal downfall.

The once emperor, the lover from his past life, his beloved in this life, and an opposing empire’s monarch who is doomed to love him, who is supposed to be good for whom?

And who is supposed to hurt whom? A hero chasing after a dream, an empire of a thousand years, a kingdom stretching across the known lands, all flashing before the eyes like a mirage. Is it worthwhile to trade a hundred years of my loneliness to give you a single lifetime of joy?

- Description from Novelupdates