Era of Castles: Starting with 99 Dragon Eggs - Chapter 420 - This Was the Bait!

A little ruffian who fought recklessly without any morals and bottomline accidentally time-traveled to parallel space and became a Key Case Investigation Team agent. The huge change in identity had him creating chaos in the police station. However, a strange miracle system helped him repeatedly solve mysterious cases, turning him into an impudent ruffian detective!

In her previous life, she was humiliated and bullied every day. Her relatives despised her and her friends played tricks on her! Her mother and elder brother died one after another early. She gritted her teeth and survived the adversity alone, but only managed to live for twenty-six years!When she opens her eyes again, she finds herself back in time twenty years ago. To swallow insult and humiliation silently and let history repeat itself? If everything couldn't be changed, what was the point of her rebirth?! Who can stop her now that she defies her destiny and her abilities are emerging? In front of others, she is an ordinary student with an indifferent personality, isolated by her classmates. Behind their backs, she works step by step to build a brilliant and extraordinary business network.

The blacksmith Anvil created weapons alone in a ruined world.

He came across a community, a hero universe, where there are heroes of every dimension.

All the heroes wanted his weapons,

All the monsters hated him,

All the world blessed his existence

however nobody prevented his death.

Decades later, a dimensional invasion started on earth.

Kang Shin-hyuk, a boy who can’t use mana inherited Anvil’s VIP ID and memories.

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.