Kai x demon slayer

Kai had always been obsessed with Kimetsu no Yaiba.
Other kids grew up wanting to be superheroes. He wanted to be a Hashira.

Every evening after school, he locked himself in the garage, switching on the single dusty lightbulb. The place smelled like motor oil and grass clippings, but to him, it was a dojo.

In his hands was his pride and joy: a plastic katana he'd melted together from discarded toy swords, spray-painted black with a red streak. His "Nichirin blade."

"Water Breathing, First Form: Water Surface Slash!"
He swung with all the grace his wiry frame could muster, exhaling hard through his teeth just like Tanjiro. The air whistled out of him in time with the strike.

He kept going.
"Wind Breathing, Fifth Form: Cold Mountain Wind!"
"Flame Breathing, Fourth Form: Blooming Flame Undulation!"
"Moon Breathing, Seventh Form: Mirror of Misfortune!"

Sweat drenched his shirt. His chest ached, but he didn't stop.

Then it happened.

No air came out.

Not a cough.
Not a gasp.

Kai dropped the sword, clutching his chest. His lungs refused to exhale, locking him in suffocating silence. His ribs ached like they were being crushed.

His vision blurred. The garage light flickered.

He stumbled backward, his plastic katana clattering to the ground. The last thing he saw before darkness swallowed him was the shattered reflection of himself in the window.