His Toxic Addiction - Chapter 17: Those Scumbags!!

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.

An incredibly athletic older brother, Tenryu Taiga. A programming genius girl, Tenryu Fuyuki. The two siblings separated for eight years ended up living under one roof again after facing the problem – a lack of funds for living expenses.

Fuyuki proposes a way to earn money, a core system deeply involved in people’s daily lives, a game that awards you money as a prize for defeating malicious bugs in cyber world, the 《Aries》structure. Taiga after becoming a warrior in the game relying on his inborn senses, is puzzled by the unfamiliar sensation.

One day Saionji Rui, Fuyuki’s best friend appears and is attacked by a mysterious bug― “I’ll be waiting, my prince.”. Hybrid fantasy battle of cheating siblings begins here!

The happiest thing in the world is to be able to amend what you have done wrong. She who acted willfully because of a game, was reincarnated into a time when she still had her parents’ love.

For the sake of her family, she began her life as a pro gamer.

But this time, she was no longer the Human Sorceress that she was familiar with. She was an Elven Huntress. Could she still acquire the power to be the Right Hand of God?

- Description from Novelupdates

Can you get used to dying? He has to.When a particular universe was born, its seven primordial Concepts acquired an ego. Omniscient and omnipotent, they seek since to enrich their home. To do so, they plunder other universes, capture young civilizations and plagiarize ideas. Many monsters, gods, civilizations, and races are competing for the eighth throne.Eons later, it is Earth's turn to be torn away from its Sun.Humanity begins its integration by participating in a Tutorial. Priam has the luck and the misfortune to finish the Tutorial first. Luck because his reward is a form of pseudo-immortality. Misfortune, because as the champion of his civilization, he is transported to Elysium, the most dangerous world created by the Concepts. Nine out of ten champions lose their lives there on their first day. Fortunately for Priam, he has many lives.