Invicinble Colorless Butler - Chapter 28 - 24

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.

Betrayed. Alone. Forced to survive the deadliest dungeon in the universe. As a Tulland dreamed of adventure. To be someone who sees every-place, goes every-where, and does every-thing. All he wanted was to go beyond the confines of his tiny island. So, when the Church denied him a class, he turned to the only other being that could grant him his wish; The System. And the System delivered. Tulland got Class, but not one he ever wished for. Awakening as a Farmer, he finds himself in the one place where he can grow away from the clutches of the Church — The Infinite; a dungeon whose end even heroes of old have never seen. Armed with what dregs of power the System deigned to give him, Tulland will have to figure out how to survive, and cultivate, the universe’s deadliest dungeon. Expect: + Progression fantasy with actual farming! + A very stubborn MC + Combat! Action! Plants!

He was the scion cast aside by a powerful family, and he had hoped to return to a peaceful life in the city, but unexpectedly, trouble arose once more!

The Main Character, Watari Karito, is a veteran player of a Military Shooting VRMMORPG.