The sound of leaves rustling in the wind woke Saitama from his nap. He blinked lazily at the sky above, a pale blue stretched between the gaps in the treetops.

"Huh… this isn't my apartment."

He sat up, scratching his smooth, shiny head. No buildings, no Hero Association alarms, no Genos begging for training. Just a forest — quiet, peaceful, and kind of boring.

"Did I sleepwalk into a camping trip or something?" Saitama muttered. His yellow hero suit was slightly crumpled, and his cape had a leaf stuck to it. He stood up, stretching casually, before deciding to follow a faint scent of smoke in the air — maybe someone was cooking. Free food sounded like a good way to start the day.

As he walked, the calm silence was shattered by a scream.

"Get away from Nezuko!"

Saitama tilted his head. A teenage boy with a scar on his forehead was desperately swinging a sword at some monster with sharp claws and a terrifying grin. The creature lunged forward — but before the sword could even strike, Saitama flicked a pebble from the ground.

BOOM.

The demon exploded like a firework, splattering into mist and chunks.

Tanjiro froze, his sword halfway in the air, mouth hanging open. Even Nezuko — still in her box — peeked out with wide eyes.

"Huh," Saitama said, brushing dust off his glove. "Is this some kind of weird festival performance?"

"You… you just defeated a demon… with a pebble," Tanjiro stammered.

"Demon? That weak thing? It was just in the way," Saitama replied, his face as blank as ever.

Before Tanjiro could respond, Zenitsu came crashing through the trees, screaming about another demon nearby. When he saw Saitama standing calmly next to a pile of demon goo, Zenitsu did what Zenitsu does best — faint dramatically.

"…Is everyone here this weird?" Saitama sighed.

And so, without even realizing it, Saitama's bored afternoon walk had thrown him into the world of Demon Slayers, breathing techniques, and a thousand-year-old demon king who was about to have the worst day of his life.

---

The end