The Real Rich Daughter is a Future Genius Scientist - Chapter 440 - : Appearance

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.

Luke never thought his obsession with novels would lead to his death — let alone reincarnation.After a fatal accident, he awakens in the world of Voidstar Chronicles, a novel he’d just finished reading.But there’s a catch: he’s not the hero. He’s Cassian von Luminaire, the doomed crown prince who dies before the story truly begins.Armed with the knowledge of the future, Cassian was determined to change himself and escape the terrifying fate that awaited him.But the world he’s in isn’t exactly the same as the book he read. Hidden truths and unexpected challenges blur the lines between fiction and reality.Can he outsmart fate and forge a new path, or is he destined to remain an expendable extra?—[Ding! Star System awakened successfully…]

In the first year of the fire calendar, a large-scale spiritual recovery has occurred around the world.

One year after the fire calendar, the Jingwei Division was established and began to contain supernatural beings on a large scale.

After three years of the fire calendar, Xun Xi traveled to this world full of despair. However, in front of him, there is only a diary written by himself before his death, who claims to be the future.

The diary revealed his future death.

In other words, every line and every sentence in the diary is his masterpiece.

And it will be updated!

“Others are the favored sons of the heavens who have traveled through the world. Wherever they go, they will be followed by chance. Why is it only me, where I will die wherever I go, I am just a rebel, a version orphan.”

“unfair!”

…………

Carrying a future diary in his arms, Xun Xi is struggling to survive in this desperate world. He firmly believes: My future style, I am the master!

- Description from novelbuddy

This novel is also known as The Demons Beside Me

Chen Zhao can summon demons and see Death.

“Beelzebub, use your Gluttony ability to treat this patient’s anorexia.”

“Raymond, this old man wants to regain his manly function. You know what I mean.”

- Description from Novelupdates