The Game of a Legendary Genius Dark Mage - Chapter 107

A recurring nightmare afflicted Khan's nights since the Second Impact. His dreams replayed the scenes of the crash of the Nak's spaceship, an alien race that the humans had defeated five hundred years ago.

Hanjun, who used to live alone, wakes up in a strange, old church in a different world called Eorera. In this world, there are two gods: the God of Light and the God of Darkness. A thousand years ago, the God of Darkness created demons and attacked humans. The God of Light was nowhere to be found, and people believed they were abandoned.Hanjun finds himself mistaken for being the God of Light by an old priest who was praying for help against the demons. Even though Hanjun is not actually a god, he ends up in a divine body on a stone throne, realizing he has lost most of his powers. He decides to help the humans by recruiting players from Earth through a game he creates called “God's Games Online.”He sends out gaming equipment for free to a few selected players, who will enter the game to help protect Ulon Town from the approaching demons. Hanjun also creates a game system and an NPC guide, using the old priest named Barry to lead the players.Hanjun hides his true identity As “Holy Son” and starts preparing to gather faith and regain his power to protect the people of Eorera.

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.

Everything was over. Everything had stopped.The clanking, the rattling.Even if I seemed lifeless, I still had a life.Crackle! Snap! Crack!I failed to protect Lady Succubus. I failed to defend the dungeon. I was shattered into pieces, completely destroyed.[Succession Complete!]“Succession…? Assimilation…?”Broken and broken again. With each downfall, the world’s true nature begins to reveal itself.