Fuhei Shi'er, a former killer in the world of magic, the "tyrant of heaven and earth" with zero magic power.
Because of a commission he couldn't refuse, he became the physical education teacher of Hogwarts.
"Notice: All flying classes and divination classes today will be changed to physical education classes."
On the edge of the Quidditch pitch, Fuheshier casually crushed a Golden Snitch in front of a group of uproarous students.
"What are you shouting for? Little devils! Will the Death Eaters wait for you to mount your broom before waving your wand?"
He threw away the iron knot and scanned the whole place.
"The useless person who can't finish the spell, the soft-footed shrimp who can't lift the magic wand - from today on, learn something useful."
"For example, when someone points a wand at you, how can you break the caster's neck with your bare hands?"
"Why do you think I don't use a wand? Because I'm so pure!"
Very novel setting with great potential