Not From Your World {Demon Slayer OC Story}

On the mountan

"IT'S SO SCARY!!", Zenitzu cried while sitting on the ground "Why is this guy siting down, you really piss me off!-", Inosuke was cut off suddenly a hole looked like it was ripped into the sky.
"W-Wha what is it ARE WE GONNA DIE!?!?!", Zenitzu was about to run away until a figure had fell out of the strange hole. The figure was rapped in a cloth like blanket, they were covered in blood and badly hurt.
Tanjiro ran up to them "Hey! Are you okay?!", he remove the cloth from the person to reveal a girl, her left eye had blood on it. Looks like it was bleeding before then stopped, a giant slash mark as well on her stomach. She had black hair with white tips fading into the rest of her black hair making a gradient, Tanjiro checked for a pulse.
"............", nothing.
Desperate to find a sign of life he keep searching.
"T-T-T-Tanjiro what just fell........AHHHH A PRETTY GIRL IS DYING DO SOMETHING!!!!", Zenitzu screamed as he saw the body in front of him.
"Eh? Are corpses falling from the sky now?",inosuke walked over to the body and kicked it.
"Inosuke! Don't disrespect people like that!", Tanjiro yelled at Inosuke, but suddenly...

".......mhmmm.........", Tanjiro's eyes glowed with hope, she wasn't dead! But how? She didn't have a pulse earlier.
"mmmmm........mhm....GRRRRR....", suddenly the girl had jumped up, her left eye bleeding again, black ink like liquid started to stream out of her wound and eye. "W-W-WHAT IS GOING ON!?!?!",Zenitzu screamed and started to panic. "SHE'S A DEMON! LETS CUT OFF HER HEAD!", Inosuke ran up to her, aiming his swords at her neck. The girl was able to doge him in time, but she fell over soon after.

"GAHHWWRRRrrr................GRRrr...mHm!", the girl puked up what looks like black ink, she seems to reject the darkness in her, her once black hair faded into a light blue and a small purple gradient. Her wound disappeared and her left eye healed, when Tanjiro saw this he looked to Zenitzu who was absolutely terrified then at Inosuke who was just as confused as Tanjiro.
This girl who was just a demon a moment ago right? And she turned back into a human, does that mean Nezuko can...

*cough* *cough* "ugh.......................mmm? O-Oh! Umm hi?", she looked at the men in front of her. A blonde boy who seems to be scared for his life, a boy with a bore mask on, and another boy with red eyes and a strange scar. "What the hell are you? Doesn't matter a demon is a demon!", But before he could even get a single swing on her, she had disarmed him in record time.
"Hey! That was quite rude there- *cough* ah! Sorry about that I'm Cyan nice to meet you."

"I uhh...think you all deserve a explanation, long story short I fell out of the sky and ended here! Strange huh?", Tanjiro looks at her. "Are you a demon? Ah! Not being rude or anything at all!", Cyan turned and faced Tanjiro while still holding Inosuke who was pinned to the ground.
"Well it's gonna be a long story, even if I write it out I bet hardly anyone will read it! And well because you asked."

Let's get started