It's Actually Not Easy Wanting to be a Supporting Male Lead - Chapter 1.7

After dying in a tragic accident, Oscar was reborn into a lowly tribe in an ancient world of great magic where only the strongest survives. Following the decimation of his family, his only solace comes in the form of a remnant which resides in his body.Live the tale of powerful warriors and deadly monsters, and tell the story.

Arthur Blackwynd didn’t expect to survive the strange and terrifying event that happened at sea. Even less did he expect to wake up in the DC Universe a world he’d only ever read about in comics.Armed with the Shadow Monarch System,the ability that grants him control over shadows and an undead army, Arthur is both awed by his new reality. As a lifelong comic geek, he knows the heroes and villains like the back of his hand Haunted by questions of why he’s here, Arthur struggles to find his purpose. Will he embrace the darker side of his newfound powers and become a villain, or will his sense of justice lead him down a different, unpredictable path?“why the likes of Raven seems to be watching my every move?” In a world full of gods, monsters, and legends, Arthur must decide who he will become and what role he’ll play in shaping the fate of the DC Universe.

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.

This is a story that follows the courtship between a stone from Hell and a god from Heaven that begins in the underworld and spans for three lifetimes in the mortal realm.