The Main Heroines are Trying to Kill Me - Chapter 323: The Emperor’s Fear

Outer Sect Disciple Chen Yu, assimilates within his body a fiendgod heart.

The heart, is the backbone of life, the human body’s fatal vital point. And it can be said that Chen Yu’s heart is actually his strongest defense point, and permits him to overtake demonic beasts, or divine beasts unlimited potential.

Henceforth, he steps onto the stage and surges forth on a magnificent scale, in a heart-rending mysterious journey.

Talented as a cloud, an unparalleled supreme talent.

10,000 races glorious, cross boundary battles.

Only my heart, eternal!

- Description from Novelupdates

200 years after the world has ended, the laws of society have long been forgotten.

____this story sets in Japan that developed a little different history from yours.

This is how a Japanese Princess relieves her stress of the day by using the latest VRMMORPG, and while playing the villain there, the first town turns into whirlpool of chaos, smashed the underground organization in one hand and went for a coup. It’s literally a playtime diary of a girl who is called as “Genocider-san”, “Roaming Last Boss”, “A different person plays the game”, “Raid Boss”, “Ruthless”, “Calamity”, and such by the players.

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.