Wortenia Senki (WN) - Volume 5 Chapter 18

It was supposed to be a perfect deal in which both parties got what they needed. However, after the child was born, he tore up the agreement with discontent and told her, “Who said that we’d only have one child? I want twins! Twin brother and sister! You’ll continue giving birth to more children until you bore me a pair of twins!”

Damien reveals an ugly truth.His sister and only family, Ahara, leaves the house every midnight whilst he's asleep—a time that he soon discovers is when man-eating beasts named Rouges start hunting for prey.Unable to question her directly, he decides to investigate her and quickly figures that Ahara isn't human but rather, a vampire hero who saves them from beings like herself coming from a world she calls Gibbous—a place where entities like vampires, wizards, and beast shifters alike reside. What’s more, he also learns that the real reason behind his parents' death was the leader of the Rogues, who's rumored to have escaped after Damien’s father almost killed him.A series of fateful events lead to Damien’s long-lost power reawakening in him, and he finds himself with no choice but to return to Gibbous, a strange world where power means survival, and weakness leads to death. As such, Damien enrolls in an academy to train his newfound abilities with one thing in mind...Becoming more powerful.However, he soon discovers that the path to power is one filled with troubles and pain, and he isn’t alone in this lust for more at the academy. It’s a bloody competition against time and formidable opponents, and only those willing to sacrifice their comfort are the ones who can attain it.With a deadly foe lurking in the shadows somewhere and a strong desire to protect his sister, Damein has no choice but to fight.The only way is up, and he is going to be standing at the top of them all, ready to counter any enemy.

After transmigrating into a SF (Science Fiction) novel and enduring cruel hardships, I ascended to the throne as the Emperor of the Galactic Empire.[Welcome to the Integrated Dimensional Community.]As the community’s Lone SF Transmigrator, I unleashed the poison of new cultures on the uncivilized primitives of the Otherworlds.-Let there be light. To judge the horde of evil, the Apostle of the Goddess sent down a Graviton Surge. Thus, in that place was light along with a massive explosion…-The Grand Duke of the North has shown great interest in your Heattech…-I, as a Namgung, am thankful for the grace akin to the vast sea provided by the Great Hero. By virtue of the Vibroblade bestowed by the Great Hero, the nefarious Demonic Cult has…It seems like these Otherworlders can’t get their sh*t together.

An Individual from Earth finds themselves in the Shinobi World, equipped with a Scientific System. From that moment, he delved into scientific research far ahead of its time.