Chapter Text
The person standing beside Stiles’ jeep looked like Stiles. He smelled like Stiles. He sounded like Stiles. But he didn’t move like Stiles. Stiles was always in motion, constantly twitching and fidgeting like it hurt him if he stood still even for a moment. But now the young man staring at Derek was perfectly motionless. He stood calm and still, the way the nogitsune had.
The stillness only lasted a few seconds before Stiles was back to moving again, but it had been enough for Derek to see. That was all the proof Derek needed. A few moments of stillness was more significant than the phone call from Scott. Scott had been worried Stiles was hurting and didn’t feel comfortable talking to him, due to some argument that hadn’t made sense when Scott had hinted at it over the phone. Looking at Stiles now, Derek feared that the situation was much worse than Scott imagined.
“Who are you?” Derek asked.
“Forgotten me already?” Stiles asked. “I’m hurt.”
He had the smile right, the teasing tone of it, but there was something in his eyes, a nervousness that he couldn’t conceal. Whoever or whatever this was, standing here in Stiles’ body, he knew he’d been made. He tossed his bags into the back of the jeep in a way that was so casual it wasn’t casual at all. He was trying too hard to seem normal but Derek could hear the too-fast pounding of his heart.
Derek stepped forward. He grabbed Stiles’ shoulder and shoved him up against the side of the jeep, fear and anger filling him in equal measure. His fingers squeezed into Stiles’ shoulder, holding him in place. He wished he could thrust a hand into Stiles’ chest and rip out whatever it was now wearing his skin.
“What are you?” Derek snarled.
“Derek, dude, I thought we were past the whole shoving-me-into-things stage of our relationship,” Stiles said, tugging ineffectually on Derek’s arm.
“Tell me what you are.”
He was right in front of Stiles, glaring into his face, and so he saw the flicker of something in Stiles’ eyes, like a spark of silver dancing across his pupils. Then Stiles’ expression changed, his nervous humour vanishing into something cold and hard.
“You’re hurting him,” not-Stiles said.
“Who are you?” Derek asked again.
“What are you going to do if I don’t tell you? Punch me? Rip out my throat with your teeth? Anything you do will only hurt Stiles.”
Derek’s fingers loosened their grip. He wanted to tear this thing to pieces but he couldn’t. That was still Stiles’ body. Stiles was still in there. Was Stiles able to feel this? The not-Stiles had said Derek was hurting him, but how did he know if that was true? It could be that Stiles would feel any pain Derek dealt this creature, or the thing might be bluffing. Could he take the risk?
He knew he couldn’t. He’d already let go of Stiles’ shoulder because he couldn’t. Here was an enemy he couldn’t fight. Not-Stiles seemed to read that decision in his face. It thought it had won, but Derek couldn’t just accept this. They’d freed Stiles from the nogitsune, there had to be a way to free him from this too. Stiles couldn’t go through that hell twice.
“Take me instead,” Derek said.
“What?”
“Let Stiles go. Take my body instead. I’m stronger than Stiles, more powerful. Whatever you need a body for, you can have mine and it will be a hell of a lot more use to you than that skinny thing.” Derek gestured dismissively towards Stiles’ body. He hoped the thing would listen. He needed the thing to listen. He didn’t have anything else that would let him fight a creature possessing a human boy, but he could do this. He couldn’t just stand there and do nothing.
“I won’t even fight you,” Derek continued. “Just do whatever you need to do. Take my body, take me over, and I won’t try and stop you. I-“
Not-Stiles held up a hand.
“Hold that thought a moment,” he said. He tilted his head a little, as though listening to something Derek couldn’t hear. Derek bit down his fury. He was trying to save his friend and this thing wasn’t even paying attention to him. He hated this thing like he’d hated few other things in his life, and he couldn’t even lash out because attacking this thing would only hurt Stiles.
Not-Stiles focused back on Derek again.
“Why are you doing this?” he asked.
“I wouldn’t expect you to understand,” Derek said. This creature, whatever it might be, was willing to slip inside the skin of an innocent teenager. It wasn’t going to care that Stiles was one of the bravest people around, fighting with nothing but hope and a baseball bat in order to save his friends from threats that were far more powerful than he was. This creature couldn’t know how smart Stiles was, the way his eyes sparkled with humour, the way he would protect someone he didn’t even like just because it was the right thing to do, even after declaring he could leave them for dead. This creature couldn’t possibly know why Derek was willing to risk everything. The world needed people like Stiles, more than it needed people like him.
“Are you in love with him?” not-Stiles asked.
Derek considered snarling, or denying the truth, but Stiles’ life was at risk here. Maybe the truth would be worth something.
“Yes,” Derek said.
There was a long moment when neither of them said anything. Not-Stiles stood there, far too still, looking Derek in the eye.
“Very well,” not-Stiles said. “I – excuse me.”
He went quiet again. Derek’s fists were clenched at it side, tense with the need to hit somebody and the knowledge that he couldn’t.
“Sorry,” not-Stiles said, “Stiles was getting a little loud.”
“You’re talking to him? He heard me?” Derek felt a sudden rise of panic. All the time he’d known Stiles, he hadn’t dared to show how he felt for fear of how Stiles would react. And now Stiles knew. Stiles was probably disgusted with him right now.
“He heard everything,” not-Stiles said. “So here’s how it’s going to work. You’re my new bodyguard. You will protect me with your life because if anything happens to me, it happens to Stiles too. You will come with me where I need to go. When we get there, there’s a ritual I need to do and then I’ll set Stiles free and trade him in for another model.”
“Why not just do the switch now?”
“I need his spark.”
Stiles could do magic. He wasn’t exactly Merlin, but Derek knew Stiles had the ability to work mountain ash and possibly other things as well. Deaton had hinted that Stiles had a spark of magic in him. If the thing inside him wanted Stiles for his magical abilities, there was no way to be sure it would give Stiles up later. But what other choice did Derek have?
“OK,” Derek said.
“Great. Get in.”
Not-Stiles went round to the driver’s side of the jeep. Derek climbed in the passenger side, hoping that this ritual wouldn’t take too long. He wanted to hurt someone. He wanted to make someone bleed.
Not-Stiles started the jeep up and then fought to put it into gear. He started driving, the jeep lurching forward. After a few seconds, he pulled the jeep to a halt again. There was a subtle shift. If Derek hadn’t been watching closely, he might have missed it, but then the fingers on the steering wheel were twitching slightly as Stiles slid the jeep effortlessly into gear and started driving as smoothly as was possible in this car.
“Stiles?” Derek asked.
“You’re an asshole,” Stiles said.
“What?”
“You can’t just declare you’re in love with me and offer to trade your body for mine without even bothering to check how I feel about any of this. And, seriously, what the hell? Where did that even come from? You’ve barely spoken to me in... well, since the Darach thing. You’ve barely stayed in the same room as me since then and I figured that was because you hate me since before then most of our conversations were more arguments than discussions, and then you take off without a word after nearly dying in Mexico. How does any of that translate to love in your mind?”
Derek couldn’t be certain this was Stiles now talking to him, but he sounded like Stiles. The same tone of voice, the same way of flailing his hand as he spoke, even though he was driving and Derek would have felt more comfortable if Stiles had kept both hands on the wheel. Everything in his posture and voice was so very much Stiles that Derek decided to believe it, until he had evidence to the contrary.
“You were better off without me,” Derek said.
“And you’re the one who gets to decide that? Like you get to decide that you can offer up your body in trade.”
“I didn’t know how else to save you.”
“Because you’ve got to save me. Defenceless Stiles is the damsel in distress you’ve got to step in and save with your goddamn martyr complex. Have you forgotten the times I’ve saved you?” Stiles reached across and jabbed Derek in the arm, never taking his eyes off the road.
“Of course not,” Derek said.
“Of course not,” Stiles echoed, “but still you had to step in and play the self-sacrificing hero even though I had everything under control.”
“Everything under control? You’re possessed! By some supernatural, evil... something.”
“Aisling’s a hell of a lot nicer than you are.”
Derek was thrown for a minute. “Aisling?”
Stiles waved a hand towards his head and said, “My hitchhiker.”
“You’ve named the supernatural creature that’s possessing you ‘Aisling?”
“Of course not. I didn’t name her anything. It’s just what she’s called.”
“She?”
“Yes, she. Aisling identifies as female.” There was the briefest of pauses, then Stiles said, “Ow! OK. She is female. Apparently gender identity is extremely important when you don’t have your own body and I need to be more respectful of that.”
“She can hurt you?”
“She’s in my head and can root around in my memories. She just pulled up a memory of Scott whacking me over the head for being an idiot. It’s not actual pain but it’s...” He trailed off, waving a hand vaguely.
“Sounds pretty damn close,” Derek said. He was thinking of his own memories. Of the way the past could surge up and take control and make him feel like he was back there in some of the worst moments of his life. To have something inside his head who could stir up memories like that deliberately; he couldn’t even imagine how terrible it would be.
He smelled blood. His own blood. His hands had clenched into fists without him even noticing, and now his claws were digging into palms. He forced his claws to retract, those stings of pain already vanishing.
“You OK?” Stiles asked.
“You’re asking if I’m OK? You’re the one who’s possessed.”
“Yeah but you’re the one who looks like you want to punch yourself in the face.” Stiles shrugged.
“How did this happen again?”
Stiles shrugged again. His focused on the road in front of him, driving along. The silence wasn’t like Stiles but Derek still had a feeling that Stiles was in control. Assuming he wasn’t being played like a sap. How could he trust anything that Stiles said right now?
“Apparently the fact that the nogitsune was in my head left an opening, a way for other spirits to sneak in. Don’t worry, Aisling did a ritual to shield me so no one else is going to start possessing me. It’s already crowded enough in here.” He tapped a finger against the side of his head.
“The creature possessing you did a ritual to block against possession?”
“She was already inside at that point so it didn’t cost her anything and it means...”
Stiles stopped talking. His posture shifted faintly. Stiles wasn’t in control anymore.
“Aisling?” Derek asked.
“Nice to meet you, Derek. Stiles has a whole lot of interesting memories about you.”
That was said in a voice that was calm and pleasant, but it could so easily be a threat. Stiles knew so many of Derek’s secrets. If this thing was in his head and had access to all of his memories then she knew them all too. One word, and Derek’s darkest secrets could become public knowledge. She had power of him as much as she had over Stiles.
“Your admission surprised him, you know,” she said. “He really didn’t think you cared about him. Especially after you abandoned him.”
Derek’s hands had relaxed a little. They tightened into fists once again.
“That’s nothing to do with you,” he snarled.
“Why did you come back, Derek?”
“To help Stiles.”
She punched him on the arm. There was almost no pain because she only had Stiles’ strength to call on but even so Derek wasn’t sure why wanting to help Stiles warranted a punch.
“Now you want to help him?” Aisling asked.
“What do you mean?”
“Where were you when...”
She broke off. There was a twitch. Stiles adjusted his grip on the steering wheel.
“Sorry,” he said. “She shouldn’t have said that.”
“What was she on about, Stiles?”
“It doesn’t matter.”
There was no obvious sign of a lie, but there was unmistakable pain in Stiles’ voice. He reached out and turned on the radio, fiddling with the controls to try and get his jeep to play a station that wasn’t entirely static. Stiles didn’t want to talk. Given how little control Stiles had over anything else right now, it only seemed fair to give him this. Derek didn’t press the issue.