Kiss Me if You Can - Chapter 18Vol 1.

This is an Isekai styled story, written from the point of view of the protagonist.

Discover the secret of the new, unknown world with Peter, as he sets his first steps in an empty, ruined city. Meet new people from all around the globe. Fight, laugh, and cry.

Lambert, one of the great generals from Regios kingdom was suspected for planning a rebellion against his lord at the end of unification war, he died an unnatural death. Two hundreds years later, when the era has changed and Regios kingdom entered it’s peaceful era, he accidentally revived as a demon called Undead Knight.. Lambert whose entire body was wrapped in a flashy Demon Metal[Organ] set out on a journey to punish the wrongdoers while enjoying the peaceful sight of Regios kingdom. But…….. This peaceful era was basically an easy mode for Lambert, the greatest general of the chaotic era.

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.

Idol show for dead people?Rayen was suddenly thrown into a supernatural idol show after meeting an untimely death at the peak of his career as a band vocalist.Upon waking up in a strange building, with a creepy stalker fan claiming to have written his entire biography, and a strange jukebox demanding him to perform, he learned of his death and found himself in a bizarre situation.[Please select a song to dance.]“What? Dance? I don't know how to dance!”[Select a song or disappear?]“Ain't no way I'm gonna dance!”[If you want to revive, become an idol.]“Screw revival! I don't want to dance!”