Moto Sekai Ichi'i no Sub-chara Ikusei Nikki - Chapter 42: A Loner’s Scheme

“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.

800 years ago, 3000 dimensional gates opened across the entire world. In that moment, it was as if 3000 different colored eyes opened across the world as hordes of monsters swarmed out of these gates like tears.

Some could destroy city walls with one strike; They had bodies the size of a giant and fed on humans

Some latched onto humans, absorbing their bodies’ nutrients and enslaving humans

Some infiltrated the humans’ cities, disguising themselves as normal human beings while feeding upon human blood to sustain themselves.

In a night, the Human race fell to the bottom of the food chain.

The world had turned into a paradise for monsters…

- Description from Novelupdates

Leon was your typical guy, perceived as weak in his school because his skills hadn't awakened, even though they usually did at the coming of age. He attended the prestigious Milham's Magic Knight Academy, where snagging the top spot meant automatic entry into the esteemed position of a Magic Knight in the country. Unfortunately, Leon found himself in the lower caste, labeled the most useless student. To top it off, he was tossed into a class that served as a sanctuary for oddballs and delinquents. Yet, he couldn't care less, as becoming a Magic Knight wasn't his goal.Everything shifted when he crossed paths with Shredica, a woman hell-bent on becoming a Magic Knight at any cost. Observing Leon's lack of ambition and his apparent detachment from the academy's pursuits, Shredica saw an opportunity. She decided to exploit him as a pawn in her ascent through the academy's hierarchy.Yet, unbeknownst to Shredica, Leon was not the complacent, unremarkable figure she presumed him to be.

In the vast Marvel universe, where superpower was still slowly growing in its infancy, several peerless superheroes tried to find their path in The Marvel Universe. A young adult named Ron from modern Earth unwittingly stumbles into such a world and begins his journey with an unknown power. This is a magnificent yet unknown true marvel world! This is the story of a normal young adult and his adventures!

- Description from Novelupdates