Level 1 Strongest Sage 1 - Chapter 25Vol. 2 - - Growing Family (Mai and Mei)

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.

He died on the wedding of the girl he had a crush on, after a long and successful career. After convincing Yama to send him back to the world, he decides to fix the areas in which his life went wrong. Realizing the lack of love and romance in his past life, he sets out to conquer the hearts of various women.

One will to create oceans. One will to summon the mulberry fields.

One will to slaughter countless devils. One will to eradicate innumerable immortals.

Only my will… is eternal.

We have all heard the legends of great wizards, but do we know how those stories begin? Ardan Egobar, a young man living in a remote corner of the New Monarchy Empire, does not. He doesn't realize that this story is about him. Not yet...In a world where steam locomotives chug along iron rails, where massive airships hover in the skies, where in the cities you might encounter orcs in suits involved in organized crimes, dwarves with cigars controlling major banks, or elves strutting down fashionable boulevards, where humans have built vast nations on the brink of a world war, almost anything seems possible.Maybe, in such a world, even an ordinary young man, the last of the mountain hunters, might one day become the greatest wizard in history.