Legendary Architect of Apocalypse - Chapter 102: Advantage of the Rules

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.

In a world where countless web novel universes collide, where soldier kings, mercenary overlords, god-tier tycoons, and even demons wage war against each other—where protagonists rise, seduce breathtaking heroines, seize endless opportunities, and battle for supremacy—there is one man who can suppress them all.A man who has finally crossed into another world.When he opened his eyes, he found himself in the body of a young man named Veil Lancaster.“A villain destined to be beaten to a pulp by the protagonist? Am I really just a side character?” Veil muttered to himself.But why should he accept that fate? His father held absolute power, his mother was a legendary business tycoon—what made the so-called protagonist superior to him?Fortunately, at that moment, he successfully awakened the Villain System.One day in the future—“Veil! You crippled me, stole my opportunities, and even took my woman! You damn villain! You’ll suffer divine retribution for this!”A protagonist roared in fury, coughing up a mouthful of blood.Veil smiled gently and said, “I didn’t do anything… This was simply your fate.”“A pawn has only one destiny—to be placed exactly where I want it.”Remember this.I, Veil Lancaster, only wish to be a charming and sinister villain.

He rose from abjection and achieved eternity in glory.
He embraced the prettiest beauties and killed the strongest opponents.
He was able to shift the clouds into rain and cover the sky with one hand.
He could overrun the entire world and go anywhere as he pleased.
He pacified wars and held the world in awe.
He was matchless in the world.
However, his hair turned white overnight for his beloved woman and he was on the verge of death.
He was surrounded by enemies who were trying to take his life.
He struggled his way to become mighty and fought for everything he cherished.
For this age, he was the only king of the Dark World.
His name was a byword for might.
As a man living in the world, his only ideal was to pursue brilliance.

Eren Idril died as an old, decrepit, and piss-poor adventurer by the maws of a D-Rank monster. He had a lot of unfulfilled dreams and desires that couldn't see the light of the day after the light in his own eyes died down.

But fortunately for him and unfortunately for the world, that wasn't his end. Eren was somehow dived back in time when he was a mere teen, attending Lionheart Academy for adventurers.

When life gives him a second chance, Eren decides to exploit it to its fullest. Experience his vile deeds as he partakes in them without feeling the slightest bit of hesitation.