Interstellar Beast World: All My Husbands Are Powerful and Rich! - Chapter 147: The missing king

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

The Spirit Blade Sect was founded in the year 4233. After thousands of years of producing first rate Xiuxian geniuses, it had become one of the five biggest sects in the Ten Thousand Celestial Alliance. The head elder, Immortal Feng Yin is one of the seven Executive Elders of the Ten Thousand Celestial Alliance, with a cultivation that can shake the whole world. The Spirit Blade Sect is dedicated to peaceful development, and holds the core values of Truthfulness, Kindness and Loyalty. In order to expand the sect and bring in new blood, all heroes and geniuses have been welcomed to attend the Celestial Gathering.

God: I shall bestow the Saintess upon you.
Pope: W- wait a moment! This is a boy!
God: That is the Saintess.
Pope: ??????

And just like that, the Saintess was raised by the church for fifteen years without any questions asked…

- Description from Novelupdates