I Was Rejected by the Main Character in a Romantic Fantasy - Chapter 28: Training Monster...!

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.

Twenty years ago, she was taken in as the Lin family’s young heiress through a twist of fate. But mistakes would eventually be corrected one day. When the real daughter of the family returned and her foster parents begged her to stay, she obliged. Unbeknownst to her, this was actually a scheme disguised as familial affection. They only kept her around to squeeze her dry of all her value!

The world was destroyed, torn to shreds by the war as it raged on. With the falling of nuclear bombs, the mutation strangely adapted and became an entirely new element.Those who couldn't withstand this mutation became beings tethering on the edge of life and death, becoming undead.Only a small population remains on the earth now.In this small population, some can adapt to the mutation and awaken unique powers in the apocalypse, while others are entirely unaffected, still like normal people.Ray was just a normal E-class awakener, but a faithful purple crystal changed everything.Through the purple crystal, a “system” activated inside him, which could allow him to get stronger the more he spreads his genes.Necromancer, wizard, martial artist to sorcerer - every single skill was possible as long as he spread his genes.From that moment, Ray walked the path of spreading his genes “for the sake of humanity.”#no ntr, yaoi or yuri

After being reborn, Bella Green is determined to punish the scum, slap faces, and sing her way to the pinnacle of life. However, she is accidentally picked up by the person she least wants to see and taken home as a cheap 'brother.'Faced with the naughty yet particularly disobedient little Demon King, Mason Bennett sternly instructs: “No fighting, no skipping class, no dating!”One day, the little Demon King shows up on television in a stunning long dress, and Mason Bennett is furious, immediately tying her up and bringing her home for an in-depth lesson!!Looking at her suitors who were beaten up and unable to take care of themselves, Bella's eye twitches, what about the promise of no fighting?Being forcibly dragged out of the classroom and carried home by a certain jealous king while attending class, what about the promise of no skipping classes?Finally coaxed and deceived into the civil affairs bureau, Bella teared up, damn it, what about the promise of no dating!!!