Witch, Fireball and the Evil God of Steam - Chapter 25: Saint

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.

“Wait... Where am I and... who am i?”Just after he thought he was successfully betrayed and killed by his most favored surbodinate. Taylor finds himself on the floor of a remote alley“Don't tell me I got reincarnated?” Hutton muttered with a look of disbelief on his face.P.S; Join the novel discord server for any announcements or questions and answers sections

She was the head of a powerful, medicine-orientated aristocratic family.

Crossing through a millennium, she ended up in the body of the General Household’s “trash” young miss, whose engagement with the Crown Prince was just broken as she suffered under everybody’s taunts!

In the drafting feast, she was re-engaged by the Emperor to marry the famous disabled prince!

Everybody laughed, a blind trash with a disabled wastrel. What a perfect match!

However, they didn’t know that in her hand, she grasped the long-lost primordial pill recipes! Her practice in medicine had reached the apex! Her contracted beasts were unique in the world!

What was the most frightening, was the disabled prince she was engaged to…….

A black-belly full of dirty tricks, with a heaven-opposing cultivation physique, he defeats all geniuses!

In his wheelchair during the day, yet entangling her in bed as he trained his waist muscles… MF! Is he really crippled!?

Chi Yan had always had a weak constitution, and ghosts had always tried to kill him. He had tried many ways to change his situation, but it was all futile.

Coincidentally, Third Master Ye of Shiming City passed away, and a priest informed Chi Yan that Third Master Ye possessed the “look of demon,” Carrying a bit of this man’s ashes and installing an altar for him at home could help control the evil spirits around Chi Yan.

Left with no choice, Chi Yan took a gamble. Amazingly, it worked. However he didn’t expect that he’d be instead be haunted by the most persistent ghost of them all.

Obsessed with love, undying resentment, possessed by evil.

- Description from Novelupdates