Lord of Flames - Chapter 95: The army marches! The Lion Clan’s countermeasures!

Living things really are ignorant – the greed to obtain the key to knowledge and the fundamentals of energy overpowers them. Little do they know that knowledge is full of lies and energy is the root of destruction. Us, mages, have mastered travelling through space and time. We are invincible, we can turn worlds into dust and you, mere ants, will be wiped out with no trace.

-Mage Adam

An A.I.(Artificial Intelligence) gets reincarnated into a world where he becomes a mage.

The world experienced a cataclysmic change, and countless spatial gateways appeared out of thin air.

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.

Cain was an ordinary boy who loved creative works, especially when it involved anime and games. Suddenly, he found himself in a strange space with an extraterrestrial creature, a cosmic horror called Bishop that he couldn’t explain in words besides scary.Given the authority of a King, he was tasked to create dungeons in the multiverse in order to change his future. He had been turned into the Dungeon Maker. The more known his dungeon was, the stronger he became!Rias: What are you? A Devil?Dante: Now, now. What are you? Wow, I drank too much. Look at her, a sexy devil.Zoro: Where am I? Is that a sea monster? Good, I will bring meat for Luffy.Helldiver: For Democracy!!!All worlds became connected due to the dungeon. However, don’t worry!Everything was under his control.