Boss’s Death Guide - Chapter 124 - Foreign Friends

Floren, the most renowned realm of all realms, yet forgotten by all. The soul of a person from Earth accidentally crashed into this unexplored realm, ending up in a dragon egg. Transforming into a crimson dragon with the mindset of a human, Claudius was different from other dragons. He only wished to live an easy life, enjoying his lifespan of thousands of years to its fullest. However, the world is not such a forgiving place, dragging Claudius into countless struggles and death battles. Is it really possible to live a leisurely life?!

- Description from Novelupdates

Eli was transmigrated to a world of magic and became immortal.

He had endless life and could never die.

“Huh? I’m talentless? Then, I’ll just train for as long as I need, even if it takes 1000 years. That should be enough for me to become strong.”

“The skill is hard to learn? Then, I’ll take a few dozens of years to research it. There’s no way it’s that hard, right?”

“What? I can sacrifice my life force to gain spirit power? That’s a bargain!”

“The enemy is here? Hell, I’ll just hide for 10000 years. Let’s see if he can outlive me. I’ll come out once he’s dead.”

This is the story of an immortal who first struggled to live in the world of magic until he became strong enough to slaughter endless worlds.

I’m a policeman, we took over the crime scene, and all the idlers and other people flashed!

Are you a detective? Do you have a formal license? Is it part of the police system? May I list you as a suspect?

Detective? Sorry didn’t hear it.

You want to reason? I’m sorry I’m not interested, but I’m standing there watching us handle the case!

Hey! Don’t move around at the crime scene, it’s you, that kid over there!

——New scum, listen to the teaching

- Description from novelbuddy

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.