Fate in Bleach: Unlimited Blade Works! - Chapter 6: The Essence of Power

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.

Kamishiro Homura is a hero who once by himself exterminated the another world invader that destroyed the military all over the world. However his extreme strength made the influential people ostracized and exiled him from the society with false accusation of [Traitor] attached to him. A few years after that, for an unspecified reason Homura entered the magician academy and he looked after the girls that were ridiculed as the [burden platoon]…!? This is the raise of the curtain of a fantasy tale of the unrivaled and invincible young man where not a single ally or enemy can keep up with him, the young man who sooner or later will be extolled as the messiah by the whole human race!

Travel to the primitive world, open up wasteland and farm land, tame animals and fish, build houses…

Jiang Xuan wants to create a tribe of his own!

- Description from novelbuddy

Good and bad luck has followed Zach ever since he was five. Poor guy. His life has been far from the sweet and peaceful paradise one might expect of the youngest son of one of only four dukes in a great Empire.But a little more excitement than expected doesn't stop him from pursuing his dreams of summoning, and perhaps his luck is finally turning once he manages to summon something great.Armed with maids, a scummy gift of luck, and a strong will, Zach sets out to live life as he pleases, even to the annoyance of those around him. First stop: The Academy.