After Rebirth, My Fiancé Helps Me Avenge the Wicked Scum - Chapter 54 - Settling Accounts (Part 4)

Brutality is my style of conduct! If you can't accept that, I'm ready to fight—that's who I am!Don't mess with me, otherwise, I won't mind teaching you the meaning of “The Return of the King”!!!

While returning home from a boring day of work, a black hole opened up in front of John and sucked him in. Before he was floating in the blackhole, a helmet latched on to him. "Uploading A.I under progress...Activating Survival Kit" A weird robotic sound appeared within the conscious of John and suddenly a white energy enveloped him... After opening his eyes, John noticed he was teleported to a whole new world. A world of magic and he was a user of a system. Arkon, the world John was brought too, was a medieval world which is 10 times bigger than earth. This new world held many new mysteries and this was the beginning of John's adventure. John will dominate and stir the world with his new system. Old technologies begone and use my advanced techys instead! Ha! you want to hold a politic, economical and military war with me? Sorry but my system is too broken for you all to counter.

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.

Adrien’s tale is a thunderous symphony of vengeance, mystery, and ascension. Awakened with no memory but wielding a shadow-forged blade, he traverses a fractured world where gods rule through fear and silence. His forgotten blood burns with the legacy of the Godslayers—beings once feared even by the divine. As he hunts corrupted gods and unearths shards of unimaginable power, Adrien evolves from a wandering enigma to a force capable of defying fate itself. Twisting through betrayal, hidden empires, and awakening legends, his journey is not just one of survival, but of reclaiming divinity to break the sky itself.