The Undead system - Chapter 56: Decision

This is a story of a man named Kim Sae-Jin, who one day, inexplicably wakes up as a Monster. Follow him and his perilous journey to get his life back as a Human, all the while growing even more versatile as a Monster in the process. This should be… complicated, somewhat.

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.

Transported to a female-dominated world and endowed with a submissive “shou” physique, he faces the threat of being hacked to death with a cleaver due to his “green tea” behavior.“I must change my fate!” Su Yan raised his hand and swore.However…“Little Junior Brother, I’ve noticed you’ve been getting prettier lately. Let your Senior Sister study you a bit.”“Why are you distancing yourself from me? Is it because you’ve taken a liking to some other woman?”“I’m going to lock you up at home, so you’ll belong to me forever.”

Tae-seo, a villain who tormented the main character in an Omega verse novel, suddenly finds himself reincarnated into that very antagonist role. What’s worse, he reincarnates just as he’s about to administer a heat-inducing drug to the main character!Tae-seo, the protagonist of the original story, thwarts Seo Da-rae’s plan to administer the drug and, in order to avoid triggering a dead flag, casually drinks the inducer. Reincarnated not as an Omega but as a Beta, Tae-seo expects nothing out of the ordinary to happen.“Well, causing a cycle right here is quite audacious. Or are you asking just anyone to pick you up?”Unfortunately, due to side effects, Tae-seo manifests as an Omega and experiences the heat cycle. By chance, he ends up sharing a bed with a man named Kang Se-heon.“Don’t expect me to take responsibility later. I have no intention of being manipulated by a bloodthirsty person like you.”“I don’t have any intention of asking you to take responsibility either.”Initially unaware of his relatively minor role in the original story, Tae-seo is surprised to learn that Kang Se-heon happens to be the main character’s cousin. As Se-heon starts approaching Tae-seo in a suspicious manner and even other characters from the original story oddly gravitate towards him, Tae-seo’s confusion deepens.“Yoon Tae-seo, you should choose me, even if it’s for the sake of the child.”Will Tae-seo be able to navigate through the night with Kang Se-heon and escape the grasp of the original story’s main characters unscathed?