One Night Bride: Master Blackwood's Substitute Wife - Chapter 643: Begging Her to Give Back Nannan!

[WSA 2025 Entry]Ivan Mendoza, a world-renowned robotics engineer, met his end at the hands of those who feared his genius. But death was not the end. Awakening in the body of Kael Valtieri, heir to a destitute border territory in the magical kingdom of Ardania, Ivan finds a second chance in an unfamiliar world driven by arcane forces.In this realm, magic reigns supreme, yet it is woefully inefficient and bound by antiquated traditions. Armed with the knowledge of advanced robotics and engineering from his past life, Kael sets out to merge science with sorcery, aiming to revolutionize the very fabric of magic. His quest? To uplift his impoverished territory and safeguard it against the lurking dangers beyond the border.But Kael’s journey takes a thrilling turn when he stumbles upon the remnants of an ancient, forgotten civilization. Hidden within their ruins lies golem technology—astonishing constructs far superior to anything Earth’s science could fathom. Driven by curiosity and ambition, Kael deciphers their secrets, melding ancient ingenuity with his modern intellect to forge unprecedented defenses.As Kael uncovers the dark history of this world, he learns of rifts that once unleashed monstrous beings from other dimensions, nearly annihilating humanity. Though a powerful artifact sealed these rifts, its strength is waning, and an impending cataclysm looms.Now, with time running out and the continent teetering on the brink of another monstrous invasion, Kael must wield his hybrid mastery of science and magic to confront the rising tide of darkness. Can one man, armed with the knowledge of two worlds, avert a catastrophe and carve out a new destiny?Prepare for an epic tale of innovation, mystery, and survival in a world where the past and future collide.

Haruto Hayase was a normal high school boy in his third year, living a quiet life until his younger sister, Haruka Hayase, joined the same school. Haruka’s beauty and charm made her the center of attention, quickly becoming the school’s prima donna. But when a notorious gang leader set his sights on her, he did everything in his power to protect her—only to fail tragically. Haruka was brutally assaulted and tortured, and Haruto himself suffered an agonizing death. However, in a twist of fate, Haruto is given a second chance, waking up a year before the events that shattered his life. Armed with the mysterious ‘Debauchery System Slave’, he vows to exact revenge on those responsible. This time, he will use his newfound powers of the system and charm to seduce the loved ones of his enemies. From their mothers, sisters, and lovers to their closest friends, Haruto will make them his. His enemies will suffer as he steals what they hold dearest, ensuring their downfall in the most devastating way possible.

Alex used to be a scientist in his previous life, infamous for doing questionable biological research; now he's the prince of a nation and a chosen 'Saint' of the God of Wisdom.Despite being a 'saint,' he's a top-tier schemer and a conspiracy master who considers his goals and ambitions above everyone and everything else in the world.“Power, connections, intelligence, and money... That's all that matters in this world; those who have them are supreme!” - Alex 'The All-Knowing Saint'What will happen if such a villainous person is thrown into this new world as a supposedly benevolent and kind 'saint'? Let's find out...(NO-HAREM, SCHEMER MC, TACTICS, AND STRATEGY!)

A necromancer and a saint blessed by the Constellations. That’s me.