I’ll Be the Male Leads Sister-in-Law - Chapter 502

Roan transmigrated as an FBI investigator.Several years later, a journalist interviewed the world-renowned detective Roan Greenwood and asked,“What made you persist in solving cases for so many years?”Roan tilted his head and glanced at the sports car beside him, the villa behind him, and the beautiful woman inside the villa. He smiled slightly and said,“Well, the bonus after solving the case.”“What?”

Liam Sera Banfield is a reincarnator.

He was reincarnated into a fantasy universe of swords and magic, but at a time that civilization was already making advancements into outer space.

The setting takes place in an intergalactic empire, a space opera-like universe where humanoid weapons and spaceships do battle.

Liam, who had incarnated into an aristocratic family in a monarchic society, has the ambition to one day become an evil lord.

In his previous life, Liam had unfortunately lost everything and died in despair.

— It’s foolish to live for others.

— I will live for myself.

Holding those feelings in his chest, he starts towards his second life, but is instead worshipped as a virtuous ruler from his difference in values.

Will Liam be able to safely become an evil lord?

Reborn in 2004, facing the age where pigs can be blown up, Lin Xuan, carrying the “Strongest Cottage King System”, started galloping…

- 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.