Reincarnated With The Strongest System - Chapter 677: Darling, She Bullied Us

Will, a seasoned game designer, found himself reincarnated as the disposable villain in a cliché “kicked out of the party” novel. Faced with his inevitable tragic fate, he had one ambitious dream: to turn the pitiful “losers” from the protagonist’s harem into terrifying blackened bosses who would torment the protagonist!He taught the timid and cowardly wolf-girl maid to imprison the one she loves forever by her side.He trained the tsundere, sharp-tongued loli witch to make her beloved see only her in his eyes.He guided the cold and clueless half-elf princess to use…—

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.

The world ended.Zombies and monsters rose. Cities crumbled.And Merek? He woke up in the apocalypse with a job that lets him create armor for lingering souls—spirits without bodies, desperate for purpose.Turns out, the dead don’t rest easy. Some are angry. Some vengeful. Others? Just lost. When Merek binds them into steel warframes, they don’t just fight... they evolve.Now, he leads a legion of the undead—ghosts in armor, bound to him by oath and fate.Faction leaders call him mad. Warlords want him dead. And God? If He’s watching, He’s not talking.Merek was supposed to die with everyone else.Instead, he got a support type job no one’s heard of... and a shot at rewriting his pathetic Earth-life.In this world, only the fittest survive.And Merek? He’s got undeads in steel at his side.

Time flew by. Even though their graduation was a long time ago, after countless nights and passing through fleeting time, their story is still circulated around the quiet campus of University G. This story has many different versions, but there is one thing that everyone knows to be true. Back then, that ordinary girl betrayed the genius of the fine arts faculty and yet, his love for her still remained. For her, he nearly died in a fire. For her, he gave up his chance to study abroad. Years later when they meet again, he is successful with a new girlfriend in his arms and she is indifferent with a light and clear smile. However, unknown to anyone, her longing had begun long ago and even now flooded her thoughts…

- Description from Novelupdates