I Own EVERY Class in This World: Life Set to HELL Mode! - Chapter 12: Defeating Monsters

A man who was once called the world’s strongest agent ended up becoming a teacher after his retirement, to train a new generation of agents. After many years of training his disciples, he was killed at the age of 60 by a secret organization’s ruse and was reincarnated in another world with his memories intact. Though he was surprised by the existence of magic and the strange species in that world, he quickly adapted to his condition as a newborn and took advantage of it. He acquired special magic and gained a massive amount of strength thanks to his rigorous discipline, in order to reach his goal: Resume his career as a teacher which he left halfway through in his previous life. This is the story of a man, who, based on the memories and the experiences of his previous life, became a teacher who travels through the world with his students.

[Crossover Fic]It was a silent night when a falling star broke through the sky of Westeros and collided in the Stormlands, alerting the Lords of the Realm, including King Jaehaerys Targaryen.Nobody knows where the star came from or what it brought, as the crater was empty when it cleared out. While Prince Aemon Targaryen, King Jaehaerys's son, dismissed it, the Conciliator was skeptical of the event.And his skepticism was not unwarranted, as nobody knew of the viciousness that was brought upon the Realm....No....the world.Drakken, a man from another world, rose from the star-dust and flames after the collision, lurking about the Realm with a terrifying power brought from where he came from. The people of the Realm were not ready for what was to come.

...[Inside an underground basement]“You are going to die for nothing, hahahaha,” the old man's voice thundered through the room, sending chills down my spine.Step.With a swift and ruthless motion, he lunged forward, his sword slicing through the air and slashing my throat, crimson droplets staining the darkness.“We'll see,” I whispered defiantly, my final words escaping as a mere breath against the impending darkness.Slowly, inexorably, my consciousness slipped away, and I descended into a deep, unfathomable slumber.“Huh!?” My eyes fluttered open, and I found myself seated in a bustling tavern, the air thick with laughter and the clinking of glasses.In front of me stood a captivating lady, her beauty juxtaposed with an angry furrow upon her brow, threatening to shatter the harmony of the jovial scene.“Don't follow me around!” Her words pierced the air like shards of ice, the intensity of her emotions palpable as she cast a resentful glare in my direction, before swiftly departing from the tavern....Am I trapped within the confines of a game? The fragments of my shattered common sense scattered before me, leaving me to question the very fabric of my reality.

When she woke up, Lake returned to the classroom of the third year. The classmates were in class with swords and sticks, and the teacher became a female Taoist.
The little fat man in the back seat, how to put two big hammers under his chair.
Rick found this to be a global era!

- Description from Uukanshu (translated)