Young and Beautiful Wife: Sir, Be Patient - Chapter 314 - : What Happened Last Night?

She was bored, so the Emperor accompanied her as she played in the three thousand realms and caught a phoenix for her to sit on. When she has cravings, the Emperor crossed through space to gather all kinds of delicacies and immortal fruits for her. Later on, she liked little kids, the Emperor tricked her, saying if she becomes the Empress, she’ll get her own kid. And like that, she became the Empress and got tricked by the Emperor into bed. However, she reincarnated and forgot everything…..

- Description from Novelupdates

"Your bed is cold," spoke a voice in the room that had her eyes go wide in fear. Nervously, she turned around, gulping softly to see a shadow on her bed as if someone laid down there. The man who had been lying down sat up emerging out from the shadows where he had been waiting for her.

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.

Waifus, Mechs, Magic! Witness a mind-blowing ride of spell-slinging beauties, earth-shattering mech wars, and an arcane system so deep you’ll lose yourself in its brilliance! Empires crumble, celestials clash, and the birth of legends in the most explosive, heart-racing epic you'll ever read!Jack Squire, a professional debris collector in Earth's orbit, witnesses the unimaginable — the colossal magical sigil igniting the sky above his hometown, Germund. As communications fail and soon an apocalyptic light blasts skyward and splits the moon in half, horrifying chaos dawn.Determined to seek the truth, Jack must navigate a perilous descent into a war-torn planet, where arcane magic and advanced tech clash in a brutal conflict between two empires.Osten Empire with its arcane: Magic & Spells (Essence and Slot System)V.S.Dunkelheit Empire with their war armours: Armatus (Think mecha)In this gripping sci-fi and fantasy adventure, ~one of a kind! Jack's quest to uncover the truth behind the cataclysm and save what remains of his world leads him into the heart of a war that shall decide humanity’s fate.