MTL - I Lost My Memory Before the Divorce Was Agreed - Chapter 18

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.

Aomori, who has a monster-fighting system, came to the world of One-Punch Man and gained the ability to enter various instances.

Therefore, “Founder of the Hero Association”, “NO. “And other titles fell on him one after another.

Comprehensive flow, the main world One Punch Man.

Completed dungeons so far: Pokémon – Demon Slayer – Sword – Pokémon – Digimon – Spell Return – Yokai Comprehensive World (Girls that Noragami Inuyasha can see, etc.) – Pokémon – One Piece-re0-Dragon Ball wait.

- Description from novelbuddy

In the year 298 from the era of the gods, elementary school girls Sumi Washio, Sonoko Nogi, and Gin Minowa are tasked with an important mission. They are to become heroes and fight Vertex, a mysterious enemy that is attacking Shinju-sama, the god tree that protects Shikoku, the only area in the world that is still habitable. What they don’t know, is that this fight will cost them more than they could have ever imagined.