This is an edit. Sorry it's taken so long for me to even do this... Comments and criticism are welcome, but I don't know when I'll actually accomplish anything. College is kind of busy, to say the least...
I don't own Naruto, but Muria is, obviously, mine. So is her brand of magic and her world, since they belong to my original story "Irisis."
Somehow the first thing out of Naruto's mouth was the most obvious.
"You're- you're a skeleton!" Naruto gaped openly, "How are you alive?"
Something akin to amusement crept into Muria's stance, "Magic."
She moved gracefully, practically floating towards him in what could have been mistaken for a siren's spell. "That same magic allows you to understand me. That same magic brought me to your world. That same magic binds me to both you and Kisame until I am released."
"Magic…"
"Apparently, like chakra, remember, little human?" She moved even closer to the boy, muscle-less bones sliding smoothly over ligament-lacking joints. "Please, accustom yourself to it. At least, until I leave. It would be tiresome to repeat myself every few sentences, and, well, rather boring."
She examined his unusually wide blue eyes with a laugh, a mocking, feline sound with malevolence rampant in each breath. "Boring me would not be advisable to your health, Naruto. I might decide to side with your enemy- and, be sure not to release me before Kisame does, or he may have me capture you. A Jinchuriki, a demon vessel, you? Poor boy."
Her eyes, for a moment, gained a gleam of red, before she laughed, "That would be sad, honey. Real sad, my little human."
Bravado vanished before this creature, Naruto still spoke, "What do you want, Muria?"
He flinched unconsciously from her rib bones as she brushed against his arm, finally close enough to touch him.
"I'll tell you when we're away from the other humans. The doctor's returning, and I don't think he needs to meet me. After all, what would he think of the village fox having such an 'evil' creature?"
With that, Muria vanished back into the shadows, visible only to Naruto as a glint of empty eye sockets in the mundane darkness.
Unaware of the bizarre events occurring moments before, a common medic burst into the room, muttering of demons and idiot Jounin. He glanced at Naruto suspiciously before tending to the comatose Kakashi.
Somehow, he missed the dazed expression marring the genin's face, perhaps dismissing it as remnants of a concussion or the rumored stupidity.
Somehow, he also missed the killing intent radiating from the shadows as his eyes slid over the boy in dismissal, completely unaccustomed to the feel of living magic.
Muria fixed her eyes on Naruto, observing the boy's acceptance and confusion. That would do, but the hatred from the other humans… No, that wouldn't do at all. Not against one of the few humans she'd ever found an interest in.
She would have to act if she could bare this world for long.