Wandering Knight - Chapter 86: Seeds of Calamity

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.

I met the male lead in prison.

Getting the [Boosted Gear] is expected for Issei. What if he gained it a month early and another one as well? Let the Games Begin... IsseiXHarem (if it wasn't, it wouldn't be DXD). Now has a TVTropes page! Getting the [Boosted Gear] is expected for Issei. What if he gained it a month early and another one as well? Let the Games Begin... IsseiXHarem (if it wasn't, it wouldn't be DXD). Now has a TVTropes page!

The sky thunders, Fang Yue, the nail household, dies on the street, the heavenly court blackmails, obtains compensation, reincarnates, and sees how Fang Da Devil disturbs the universe and upset the world.

- Description from MTL