Thank you BlondHairBlueEyes14 for the amazing prompt :)
Will had never been truly angry at Jem.
He had been frustrated, upset, and scared for his parbatai before, but he had never been angry before. Jem was simply a person that you could not be angry with. He was calm, and pure. He was everything that Will hoped to be, but knew that he never could be. He was comfort. He was the one person that had kept Will from ending his life, the one person that he trusted completely. It was hard to be angry at a person that you trusted with you life, and that you as you loved your own soul. But now, kneeling at his friend's bedside, Will was furious.
Jem was as white as the pillow underneath his head, his tousled silver hair gleaming in the moonlight like the quick flash of a dime in sun. His eyes were closed, but dancing rapidly under his eyelids, and his thin fingers were fluttering weakly-as if he meant to clench them into fists, but could not find the strength. His clothes had been washed, but Will could still smell the faint, coppery scent of blood. Jem's blood.
Letting out a sigh, Will ran his hands through his hair and leaned back in the chair, fastening his eyes on his brother, counting the steady rise and fall of his friend's chest. It was a soothing, familiar act, but it did little to cease his anger. He was not completely sure why he was angry, but he could not deny the emotion, and it was making him restless.
Unable to sit still any longer, he jumped to his feet and began to pace, around and around Jem's bed, tapping his fingers together as he did so, and struggling to keep from crying out in frustration. The battle flashed over and over behind his eyes:
He could feel through their parabatai connection that Jem was weakening, and he fought to get closer to his parabatai, to guard his back-
Jem turned to look at him, and something flashed in his eyes, turning them an eerie, brilliant silver. "Will!"
Will had whirled around, and had only seconds to see the claws, dripping with poison-
And then Jem, throwing himself in front of Will, arms spread wide, and the sickening crunch as the demon's talons sank into his chest, scraping against bone.
And all Will could do was scream. Catch his falling parabatai, feel the hot sticky blood against his hands, and call Jem's name, over and over-
"W-Will?" Jem's voice was hoarse, barely above a whisper, but just the sound of his brother's voice was enough to pull him back to the present.
Will spun and half ran to Jem's side, seizing his hand, studying his face.
Jem was watching him through half-lidded eyes, his lips dry and cracking, drops of blood beading at the corners of his mouth as he spoke. Will saw to his relief that Jem's eyes were a pale silver-not the dangerously bright color they turned during a particularly bad attack.
"Will? Are-are you-"
"Shhh," Will hissed, putting his hand against his friend's mouth. "Don't talk. I might have to hurt you."
Jem's eyebrows drew together in confusion. He was still not completely lucid, Will saw, and his sleep-muddled brain was having trouble processing what Will had just said.
"How do you feel?" Will asked, changing the subject before Jem could ask any questions that he did not want to answer.
His friend shrugged his thin shoulders, and then winced at the movement, his face tightening in pain. To Will's alarm, a faint cough rattled in his chest.
"James..." Will groaned, putting his head in his hands and gripping at his hair. "Why must you keep doing this to me?"
"What?" Jem said softly. "Saving you?"
"Yes!" the word was a raw shout. Will sprang to his feet and spun away from his friend, chest heaving, trying to articulate his emotions without hurting Jem. "Do you have any idea-" A sound rose in the back of his throat-it might have been a sob. "I was-"
"Will." Somehow, Jem's breathless whisper cut through Will's rant, and he paused.
"Will, stop blaming yourself."
"Why?" Will demanded. "I should have been paying attention, I should have been there."
"You were there. It was I who wasn't."Now a flicker of a smile crossed his face. "What do I always tell you? You forget to look behind you. that's why I guard your back. But I wasn't there."
"So you found it nessacery to through yourself in front of me?"
"William." Now there was a slight trace of annoyance in Jem's tone. "I swore to protect you."
Will came and sat by his friend, calmer now, but still angry. At himself, mostly. "Why didn't you just-just-God...Jem. Why did you have to keep saving me? I'm grateful, but I really-" His voice broke. He couldn't speak of the curse, and there was no way to make Jem-his only true friend-understand. Not now.
"Why didn't I just let a poisonous demon sink its claws into you?" Somehow, Jem managed sarcasm. "Because, maybe if I had, you wouldn't be here right now."
Will rested his head against his friend's bedside. "You're an idiot."
A real grin, incandescent and teasing, spread across Jem's pale face. "You're welcome."
Will lifted his eyes and met Jem's silver ones. He saw so much in his friend's gaze. Comfort. Acceptance. Laughter. Love. He saw the only true friend he had ever had. His brother. His throat suddenly felt tight. "Thank you," He whispered past the lump in his throat.
Jem's fingers closed about his wrist, squeezing gently. "What else are parabatai for?"
And somehow, Will managed a small laugh.