Supreme Taming Authority - Chapter 4: Effects of the Chaos Spirit Technique

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.

Rune was just an ordinary man from Earth — until fate threw him into Ninth Dawn, a world of swords and magic. Reborn in the frail body of a child cursed with an F-rank Divine Blessing, Rune’s new life was nothing but suffering.Branded with false accusations of rape and murder, he was captured by the Seraphic Order of the Black Veil (SBV). Brutally tortured and executed for crimes he never committed, his story should have ended there.But death wasn’t the end.Time rewound. Rune opened his eyes once again to the moment of his first reincarnation.This time, he vowed vengeance.Guided by Nexar, the Warlord’s System, Rune carved his path through blood and fire. He conquered territories, raised armies, and earned the fearsome title:The First Warlord of the Dawn.Yet even warlords fall. At the peak of his conquest, Rune was struck down by the hand of the Demon Lord — the true shadow looming over the world.And then… he returned once more.Back to the very beginning.But now, something had changed.The system reincarnated with him.Only, it wasn’t the same.Nexar had awakened anew as:Nexar, the Warlord’s Carnal System.With vengeance burning in his heart and a twisted new system at his side, Rune is ready to defy fate itself.War, blood, lust, and conquest — his dawn has only just begun.

Xu Jun finally defeated the BOSS–the Dark Demon King, in this stand-alone, virtual reality game. When he wanted to go out to browse Weibo and express his mood, he suddenly encountered a game BUG and immediately passes over to the game world.

He became the man who finally took down the Great Demon King in this world. Gratifying! The attention of millions of people!

……However, he did not know the development of this world was not the same as the game, the Demon King did not die, rather his soul entered into Xu Jun’s body; this Demon King knows of all the stupid things Xu Jun does everyday…….

- Description from Novelupdates

The consciousness of a Great Magus suddenly returned to his original body on earth, just before he transmigrated into the magic world.

Nothing has changed, it's still the same earth.

However, when he looked at earth once more as a former great magus, he discovered earth was not as simple as he knew it to be.

Hidden magus, legendary races such as vampires and werewolves, they do exist, ruling the world through the shadows.

Faced with a former great magus, who possessed as many spells as libraries, would the earth that had been ruled by a few people be able to remain calm?