Demon!Stiles fic because I really like the idea. It takes place a few years in the future.

Derek glared into Stiles’ almond-brown eyes, searching for him. His face was smirking, but he knew that the demon was in control. He knew that Stiles was locked up somewhere inside of him, scratching away at the door, trying to get control. Hopefully. What if he relented to the demon?

“You better be preparing,” Stiles’ voice said.

“For what?” growled Derek, his nostrils flaring. He hated interacting with the demon, but he knew that he needed information, and the demon was the only way to get it.

“For the storm, the war, the Prophecy’s fulfillment,” he said in an airy voice, like he was so much stronger than Derek, like he knew so much more. “You and your friends are going to be running,” he continued. “You’re going to be running from the Prophecy, from the war, and you’re going to be wondering how you were so unprepared. But Stiles, he’s been warning you for ages.”

“How?”

“Haven’t you ever wondered why I took Stiles?” the demon asked. “All those years ago, Stiles. I took him, but why?” Derek refused to answer. “I can’t get out of him, Derek. He took me in, he forced me.”

“No he didn’t!” Derek hissed, his fangs baring.

The demon chuckled, unafraid. “He was broken before I came,” he went on. “He was so… fragile already, and then everything happened and it just… traumatized him. The poor little boy. Under the protection of the wolves, the runner in the woods, Little Red Riding Hood.”

“You’re not telling me anything worth while,” Derek said suddenly, turning on his heel. He began to walk away, his teeth gnashing together.

“He wanted you to notice!” the demon called out to Derek. “He wanted you to save him, but you couldn’t. You just never noticed… you never noticed until it was too late.” Derek halted. The demon was smirking again. “Poor little Stiles, poor little in love Stiles. How terrible it is, to be undermined by your best friend, hated by your father, ignored by your unrequited lover.

“So then he became a vigilante. Didn’t you ever wonder what happened to those stray Alphas? Yeah, I took care of them. See, I’m not entirely bad. I do good things.

“But now the war is coming. The war. Oh, the war. The war between Heaven and Hell, Earth and all. You need to take a side, Derek, you and your pack. And when this is all said and done, you’re going to be wondering just how you got out of it alive. And maybe you won’t.”