Demon Slayer : The Silent Journey - Chapter 148: Butterfly Mansion

Of the ancient gods only one remained in the world. This god lived alone for thousands of years and no longer had any desires. Legend had it that during the great war between the worlds he used his powers to turn the tide managing to seal the cataclysmic rift bringing order back into the three realms. Time flew by and hundreds of years passed in the blink of an eye.

In this time Shen Li was born into the demon world. Known as the Azure Sky King she was used to living a bright and dazzling life full of successes. Little did she know that her 1000th birthday would bring misfortune to her doorstep – a politically arranged marriage with her name on it. The Azure Sky King would henceforth marry the thirty-third grandson of the Heavenly Emperor, Fu Rongjun. This arranged marriage was meant to unite the Heavenly realm with the Demonic Realm, bringing the two together. Most would consider it good fortune to be related to the Emperor.

Unfortunately Fu Rongjun was infamous throughout the two realms for his Casanova personality. As the King who called the shots in the Demonic Realm, she had the ability to quell uprisings and end wars with a swing of her silver spear – there was absolutely no way she would marry such a flirtatious idiot. She had to escape from this marriage somehow even if it meant death!

In her escape Shen Li, never expected to meet a man that didn’t belong to any of the three realms. This oddball was truly strange!

- Description from Novelupdates

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.

The story about a family's struggle to ensure that, above all else, their youngest escapes from the mines where he was born into slavery. Follow Alistar as he struggles through terror and tragedy, embarking on a road to discover himself and his heritage.

With the flick of sleeves, it overturns.
With a thrust of punch, it shatters!
It’s a vast world filled with adept martial artists!

The ancient clash of the titans brings forth the wrath from heaven.
“They send down the thunder, they send down the fire! ”
They bolted the continents separating them into a land of 9 countries covering the 18 provinces, and the world therefore, ushers into the era resonating with the Dark Ages.

However, as the things run downhills, rise forth the cultivator team comprising the big deals.

Ye Shang, a young villager with a cinder burning in his heart thus, set off into the world of cultivation. A life-changing mystery! A competition for the throne! The winner becomes king!

What’s in store for him?

- Description from novelupdates