Kuro no Maou - Chapter 457

I found a girl of unknown origin outside; she claims to be a time traveler from a post-apocalyptic era.Great calamity is imminent, with abominations spreading across the land, human civilization annihilated, and even the world itself shattering, all beyond redemption.As for myself,I am considering how to confine this beautiful girl, who has temporarily lost her powers, within my home.

When low-level healer Elias Vale stumbles upon a cursed cocoon in a forgotten ruin, the last thing he expects is to hatch the reborn soul of the Demon Queen Revantra—in the form of a scared little girl.To save her from divine execution, she binds herself to him through an ancient soul pact, fusing their fates. Now, Elias is stuck raising the former destroyer of worlds—who can barely tie her shoes, but occasionally melts furniture when she pouts.What starts as reluctant guardianship soon spirals into something far more dangerous. As Rhea (her new alias) grows stronger, older, and far too attached, Elias must keep her identity hidden from zealous church inquisitors, ambitious heroes, and the remnants of her own loyal followers—some of whom want her dead... again.But the longer he protects her, the deeper the bond grows—and the harder it becomes to tell who’s really taming who.Because the world once burned beneath her wings……and this time, she’s not letting him go.

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.

[5 Spell Books][280 Spells and Rituals][Ressuration Completed[System initializing… Synchronization in progress…][Synchronization Complete][Harem Codex Initiated]Every normal thing in his life took a great turn after he Fucked the goddess of lust.This is what I was born to become 'A Monster.' They will fear me! They will crumble in my presence! My purpose is not to save but to destroy, my legacy will be remember forever...Azrael was once the kingdom’s deadliest weapon, forged in the shadows by the criminal elders and a king who demanded perfection. But when his humanity cracked under their brutal training, they abandoned him to a witch-run asylum, branding him broken and useless. Left to rot in despair, Azrael met his end in the ward—until the witches intervened.Out of pity and defiance, they performed a forbidden ritual, combining 280 spells from five ancient grimoires. Their sacrifice gave Azrael a second chance, transmigrating his soul into a new body.He awakens with a system unlike any other: a reality-bending tool granting him the ability to charm and seduce powerful women, each conquest unlocking new powers and revealing deeper truths about his own existence.In a world where women dominate 75% of the population, Azrael uses his newfound abilities to climb the ranks of society, assembling a loyal and influential harem. But as his strength grows, so do the secrets surrounding his rebirth. Each revelation pulls him closer to uncovering the true nature of the system and the conspiracies that reach far beyond his betrayal. Is he the master of his destiny, or just a pawn in a greater game?-___A/N: Sypnosis not long, but gives all it should give, before you judge, read up to the first 15 chapters and leave a review once done.....See y'all in the book.You want a wise MC? You got it!You want an MC who will turn out not to merciful? You got it!Fast paced story? You got it!Something a little bit new, and out of the ordinary? You got it!Level up of both the MC and Villain and system? You got it![Adventure, Action, R18, Isekai, System, weak to strong, Handsome ML, Beautiful FLs, Demons, Monster Girls, Beasts, Apocalypse: All Check ..]