Death Guns In Another World - Chapter 1114 1053: Absolute Zero: Black Ice

“Compared to our time, the current generation just aren’t as reliable” they said, “Still, isn’t he the son of the Hero?” How annoying.

It’s been over ten years since the battle between mankind and the demons ended. The children of the heroes who saved the world are all grown up.

One of them, Earth, was a talented man, and everyone expected him to succeed his father as a warrior and defend his country, but Earth was always wary of his father’s title.

One day, Earth is shocked to find his father’s sword, which was used to overthrow the Demon King, sealed in his family’s mansion.

Because trapped within was the ghost of the Great Demon King who was unable to pass on and continued to roam the world.

For some reason, only he could see the spirit of the Demon King, and the Demon King possessed him through the sword.

Every day, forced to coexist with the spirit of the Demon King, they live a strange shared life, when the Demon King whispers to Earth on a whim.

“I have a grudge against your father. If you want to get back at your father and the world, I’ll train you. I’m free.”

Earth receives special personal guidance from the Demon King just to get back at his parents and the world.

Then, in the coming days. The hero’s parents, the heroes of the past, the first love, the princess childhood friend, the geniuses of the era, and the world will tremble.

Su Wan is a Realm Destroyer. She shuttles to different time-spaces using the identity of the “Cannon Fodder Ex-Girlfriend”, dedicated to plotting how to happily tear apart the male protagonist and the female protagonist. –There’s no such thing as protagonists who can’t be torn apart, only Ex-Girlfriends who don’t work hard enough~

- Description from Novelupdates

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- 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.