Realm of the Night God - Chapter 146: The Young Boy

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.

The most famous deed of this princess was her words to her younger brother Liu Ziye.

When he became emperor, she told him, “Although your highness and I are of different sexes, we are the children of the same father. Why can you sleep with so many different women, while I must be only with my husband? This is so unfair!”

And after the Emperor Liu Ziye heard his elder sister’s words, he ridiculously thought it made sense. So he immediately corrected his “wrong ways” and painstakingly selected thirty handsome youths for her to enjoy.

Chu Yu awoke in the princess’s body and realized that she had obtained a male harem of three thousand; should she take just one to drink, or keep all of them?

- Description from Novelupdates

There are three realms in the multi verse; The Cosmic, the Mortal and the Nether realm.

Hal grew up in the mortal realm with no idea whatsoever of who his parents were.

His love for relics, adventure and the occasional danger would aid him in finding a genie's lamp.

Rubbing a genie's lamp should grant three wishes, but Hal is struck by lightening instead and eventually arrives in the Cosmic realm with a large book in his mind space titled; The Primordial Cosmic Grimiore, that apparently holds all knowledge for a perpetual reign.

And so Hal's journey begins in a little city called Salmon city, in the body of a 17 year old boy also named Hal but was sold into slavery by his own father.

Hal finds out who his mother (prior to reincarnation) whose bloodline now flows unmixed in his new body is....

Join Hal as he battles mortals, Dragons, phoenixes, Gods and many more together with his harem of Beauties for the complete subjugation of the three realms.

Rainer, an amateur arcanist and college student, sought to create a new spell far surpassing the magic of the few he inherited from his grandfather. Yet the interference of an unknown event during the casting of his spell led him to be thrown through space and time.