Surprise! Tyrant's Little Crybaby Went on a Killing Spree After Being Reborn - Chapter 496 - : Of Course, I’ll Kill You

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.

Cheng Yin likes her deskmate Chen Yan for a long time, but she never dared to confess her love for him, and the phrase ‘I like you’ is a secret hidden in her heart, but she can’t help but blurt it out from time to time…
Cheng Yin: “Chen Yan, I’ll whisper something to you.”
Chen Yan always leans over quite cooperatively, “What?”
The words came to her lips, Cheng Yin blushed and changed it into: “Your pants are unzipped.”
Chen Yan: “?”
Later, this kind of useless whispering has become more frequent, and Chen Yan listened again without moving a bit: ” Speak.”
The day of the party, Cheng Yin drink for the first time, Chen Yan became two in front of her eyes, she grabbed the person with both hands, want to try to catch the real Chen Yan, only to have her hand caught, he lowered his head in her ear and said: ” Let me whisper to you.”
Cheng Yin: “…… what?”
Such bad behavior, she thought it was something bad, Cheng Yin checked her pants and made sure the zipper was closed before she lean over.
The man’s breath blew softly in her ear, laced with a bit of the smell of wine.
“I like you.”

- Description from Novelupdates

After his wife suddenly rose to fame on a variety show and asked for a divorce, Chen Yu left with his daughter with nothing but the clothes on their backs.At the moment he received the divorce certificate,“Congratulations, Host, for unlocking the Divorce Achievement and activating the Perfect Counterattack Life System.”Chen Yu made his way from catering to entertainment, medicine, and the financial industry before venturing into the field of technology.When his ex-wife Fang Yuan came to see their daughter, intending to mock Chen Yu, she was stunned by the scene before her!All those entertainment industry big shots she had tried so hard to cozy up to were now revolving around Chen Yu.Regretful, Fang Yuan wanted to reconcile with Chen Yu, but then she discovered their daughter's teacher Tong Ya...

This is a time of great powers: The vast Persia, Sparta that is founded by force, Athens with its trade and business, Thebes the rising star, The ambitious Macedonia, The twin heroes of the Western Mediterranean, The rising Rome and so on.

This is an era of brilliant stars: Agesilaus II – the last king of Sparta, Epaminondas – the Rising General of Thebes, Philip II – the founder of Macedonian hegemon, Dionysius – the tyrant of Syracuse, Camillus – the Roman dictator and savior…

This is an era of contention among a hundred schools of thought: Plato – the great philosopher, Antisthenes – founder of cynicism, Pythagoras – school of number, Democritus – the encyclopedia scholar, Hippocrates – the father of western medicine, Aristophanes – the great dramatist…

What will the hero bring to the world when he comes to this age as a humble mercenary through rebirth?

- Description from Novelupdates