Hey, this is Dagger.
This is a Natsume Yuujin-chou fic where Natsume was a yokai all along. He was raised by Madara because his grandmother, a huge, almost god-like yokai, split and left him alone. His parents were killed by exorcists whom he cursed with death. He doesn't hate all exorcists, though. He helps them sometimes, without them realizing it. He's revered as a god or a lord by the local yokai.
And that's the background.
The exorcists servants were pitiful creatures, not even strong enough to detect his presence. They dared invade his forest? The weaker yokai had fled to him in fear, claiming some young exorcists had been going around randomly exorcising weaker yokai and capturing the stronger ones. That piqued his interest. He led them to his favorite mountain temple and sat himself behind the screen door, letting his wings free to flutter free, allowed his horns to be silhouetted against the thin paper. His cat's-eye pupils glowed a deep, glorious silver. When the exorcist caught sight of him, he couldn't suppress a shiver. This was a yokai.
"You dare think yourself worthy of capturing yokai on my mountain? Arrogant human exorcist." Natsume murmured, low enough to cause a shudder. "I shall have to fix that, hmm? Can't let exorcists think they're stronger than me, eh Madara?" He snarled a laugh. The exorcist grew emboldened.
"Of course exorcists are stronger than yokai, you dumb beast!" He giggled a nervous sort of giggle, as if his mind couldn't quite believe what his body was doing. Natsume let his eyes flicker shut and his wings spread threateningly behind him, waiting. For the phrase that would seal this impudent traveler's fate. "We can exorcise you. We can seal you away." His servants grimaced. They, too, were new to this area, then, and didn't know not to insult the god of the forest.
"Toshiaki? Toshiaki!" An older man was running up the mountain path. "Toshiaki, don't!"
"So your name is Toshiaki? I curse you, then. May you only see with one Sight at a time." Natsume giggled (exorcists were such fun), then sent a small tendril of power out to the exorcist. The other watched in horror as his partner was completely enveloped in a black fog and then released.
"So long," Natsume crowed as his powerful wings pushed down and he lifted gracefully into the air. He listened to the exorcists' cries as they got quieter and quieter. Madara laughed beside him.