Rebuilding the Immortal Cultivator Clan - Chapter 328 - 334: Jade Peach

With a square halberd in the palm, and a red rabbit and horse under him, nowhere can the world go!

- Description from novelbuddy

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 a terminally ill young man awakens in the world of his favorite childhood game, he realizes he isn’t the protagonist, the destined hero, or even a major side character. Instead, he has become an extra—a disowned noble barely clinging to relevance in a world where strength determines everything. Worse, his fate in the game was to die an early, meaningless death.Armed with only his knowledge of the game’s storyline and a common system that tracks his stats and skills, he is determined to survive. But mere survival isn’t enough. He remembers a hidden easter egg from a long-forgotten anime collaboration: the Mangekyō Sharingan—a power limited by game mechanics but unrestricted in reality.With Kamui as his trump card, he walks the fine line between fate and freedom, seizing power from the shadows while avoiding suspicion. As the protagonist and his allies battle against demons and unravel the game’s grand destiny, he secretly builds his own strength—manipulating events, mastering forgotten arts, and even forging ties with villainous factions.Will he remain a footnote in history, or will he carve his own legend in a world that was never meant to be his?

One day, Zhang Chenfei met a car accident. Fortunately, he didn’t suffer any serious physical injuries. However, due to the impact of the car crash, his brain’s perception of the real world had turned into that of the novel that he was reading prior to the accident. The thing that horrified his wife, Jiao Qi, was… the Smart Brain, Louis XIII downloaded a series of books which meant that his husband would turn into a different character each time!

How will our adorable little wife deal with this kind of husband who seemed to suddenly suffer from multiple personalities?

This novel’s plot focuses on Zhang Chenfei’s changing personality based from the characters in the books, and how his wife, Jiao Qi, deal with every character as he will have to act in sync with whoever his husband’s character is. This is per the advise of the private doctor since treatment of this special condition was still under research.

As they act out their roles, they will gradually discover and learn more about the other, which they’ve never known in their seven years of living together.

- Description from Novelupdates