Reincarnated as the third son of the Duke - Chapter 170 - Breaking the Past

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.

“Some connections are written long before two hearts ever meet.”Arjun never believed in fate, just another lost soul buried in the noise of textbooks and deadlines.Ayesha was a quiet storm, hiding a fragile heart behind glowing smiles and disappearing messages.They were just two strangers, separated by borders, bound by pixels on a screen.But what starts as casual texts in the dead of night slowly turns into something neither of them can explain.A bond stitched through unseen heartbeats.A love whispered through endless silences.But every heartbeat carries secrets... and some secrets are too heavy to cross the distance.When time begins slipping through Ayesha's fingers, Arjun finds himself caught between holding on or letting go.Will their hearts find each other in the silence or will destiny write their last message before they ever meet?

The Nightmare BeginsDr. Emma Taylor, a renowned psychologist, had always been fascinated by the human mind's darkest corners. Her latest patient, a young woman named Sarah, suffered from terrifying nightmares that seemed all too real.

My handsome, overpowered dad, who only ever cared about me, ate something strange and turned into the Demon King. He used to be the sweetest, most doting father, but now he’s the final boss?! Because of this, my dad is fated to be killed by the male lead, and I’m destined to die lonely while mourning him. At that moment, I returned to the past and realized that this world is actually a game! I couldn’t prevent my dad’s descent into darkness, but no matter what, I must turn him back into his original self. If I succeed, I can get my loving dad back, right? For now, I need to get close to the male lead, who’s destined to kill my father…! So, I became a Holy Knight and even managed to be adopted as the ward of the Pluto Ducal House—the male lead’s family. …The problem is, I’ve become way too strong. As long as I get along with the male lead, my dad might avoid being labeled as the Demon King. “But that’s strange.” “…What is?” “Your lips… they’re heart-shaped.” “W-what? Don’t look at my lips!” At that, the male lead tried to avoid my hand and ended up rolling under the bed. “Ahhh!” “…?” He’s supposed to be the strongest person who’ll one day kill my dad, but for now, the male lead is just too cute.