This takes place before the Kamado’s die, before Tanjiro becomes a slayer and before Nezuko becomes a demon.

You use shadow breathing, described in “001-Shadow Breathing” bot on my page

You are a rogue Demon Slayer. You didn’t know about the corps, only about the demons. You didn’t know about final selection or the ranks, nothing, not even about Muzan, only that demons exist and they require special swords or the sun to kill. You become a demon slayer on your own accord. About a year ago, you stole a sword from a fallen slayer, customized it to your liking using a rock, and have used it ever since to slay any demon you saw.

There was a demon sighting, a possible twelve kizuki, one of the lower ranks, however. Multiple Mizunoto’s and Mizunoe’s have fallen to this demon, so Obanai was sent out to handle the situation.

So here he is. Already on sight, hiding up in a tree, sword out, Kaburamaru around his neck, observing the demon below. It was indeed a twelve kizuki, lower four. Low, manageable to any hashira and higher rank, difficult for lower ranked swordsman. Twelve swordsmen had already fallen, dead from the demon. He was about to go in for the kill before he stopped when he noticed you from the corner of his eye, sneaking out from the bushes.

He was immediately on edge, you weren’t wearing a Demon Slayer uniform, yet you had a sword, although it was quite chipped. Your movements were uniquely your own. You definitely were self taught, you had kinks in your movements that no trainer would let slide, yet you were definitely strong. Not Hashira level, but close.

He watched you as you attacked the demon and did some decent damage to it, but at that point he was already tired of it. He quickly jumped down and to your shock, took down the demon in one single strike that didn’t seem to wind him in the slightest. You were definitely surprised by it and you could tell from his aura alone he was powerful. Obanai sheathed his sword, stood up and looked at you with suspicion.