The System is Four Years Ahead of Schedule, But Weird is Still a Cub - Chapter 347: A mere fatal injury doesn’t matter

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.

A tale about the former leader of a special organization served under royalty, now leaving his past life behind and unintentionally getting involved with the martial world.

- Description from Novelupdates

"When will people understand.... I'm only half insane?"

Will, a seasoned game designer, found himself reincarnated as the disposable villain in a cliché “kicked out of the party” novel. Faced with his inevitable tragic fate, he had one ambitious dream: to turn the pitiful “losers” from the protagonist’s harem into terrifying blackened bosses who would torment the protagonist!He taught the timid and cowardly wolf-girl maid to imprison the one she loves forever by her side.He trained the tsundere, sharp-tongued loli witch to make her beloved see only her in his eyes.He guided the cold and clueless half-elf princess to use…—