The Path Toward Heaven - Chapter 790 - The Lines in the Dark Night

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.

“When the old gods are forgotten, they do not die—they wait.”In the year 1025, the Viking Age wanes.Iceland bows to Christ. The Althing governs by law. And the gods of old fade to whispers.But in the far Westfjords, something stirs.Vetrulfr, a former Varangian captain and exile, returns from the East with foreign gold, forgotten warcraft, and a hunger no man can name.He comes not in peace, but to raise Ullrsfjörðr from ash and ice; building walls, carving runes, and waging war on behalf of a dying faith.From Reykjavík to Aachen, rumors spread: a ghost walks the North once more. Some call him the son of Ullr. Others, a wolf-cloaked demon.But all will know his name.and when the Valkyries call, he will answer.

In the foreign world, the martial artists dominate the world and the sword of the emperor controls the fate of hundreds of millions of lives! Long Yu, the number one killer on Earth, after dying, takes rebirth in this new world in an aristocratic family of martial artists but faces rejection because he is unable to practice martial arts.

- Description from Novelupdates

As a naive teenager, he was unaware of his own superiority.Shang Xiaojie realized the violent man who had tricked him into a hotel was actually his brother-in-law.He struggled and tears streamed down his face as he pleaded, “Let me go, you idiotic beast!”“I may be foolish, but a beast? Can’t you at least admit to that?” he asked.After drugging Shang Xiaojie, he callously taunted, “You’re just a male prostitute who comes running whenever I snap my fingers. You’re nothing, Shang Xiaojie.”Devastated, Shang Xiaojie swore, “Mussaf, I hate you and I’ll make you regret this.”Upon his return five years later, he was accompanied by a young boy.Shang Mingming asked, “Is that man my father?”Shang Xiaojie responded coldly, “No, I don’t know someone like him.”Furious, Mussaf demanded, “Where are you taking my son?”Shang Xiaojie grinned and replied nonchalantly, “I’m getting married to another man. There’s nothing you can do about it.”