The Newt and Demon - Chapter 32: Fire Salamander Eggs

Masterpieces such as 'The Divine Comedy', 'The Theory of Evolution', 'Encyclopaedia Britannica', 'The Theory of Relativity'...Born in the history of human civilization, possess mysterious and magical powers in another world!Original sin, biological evolution, mastery of all arts...By reading the secret tomes, one can gain a variety of powers!The only trouble for the people of the other world is that they find it difficult to understand the texts from Earth.At this time, there comes a librarian from Earth...

This is the story of a modern sailor who was accidentally reborn as a soldier of the Brazilian Expeditionary Force, and finally became the largest plutocratic family in Brazil by virtue of his foresight.

- Description from novelbuddy

“Hmph, my dumb big sister is in danger!” A mischievous grin spread across his face. “Hehehehe... this gives me the perfect excuse to finally use this treasure I’ve acquired but never bothered with!” He rummaged through his belongings, carefully selecting various items. “A bit of this... and this... and a dash of this.” Boom! The explosion of energy sent a ripple through the air as he laughed maniacally. “Hahaha! It’s done! Now, all I need is a compatible host for it.” Years later... “Did I overdo it?” he wondered in awe, watching as his creation wreaked havoc, conquering world after world with ease, as though stealing candies from children.

Shu Yu transmigrated and became the original novel’s violent and brutal female Demon that caused the supporting male character, AKA hidden Boss, to become batsh*t crazy. However, right now, the Boss is just a lowly slave that was just given to her. What should she do?

- Description from Novelupdates