It was the night after a hunt. This particular case had involved taking down a Greek God. It should have been simple enough; stab the creature through the heart with a wooden stake soaked in the blood of a lamb.
But Castiel had made a mistake by underestimating the God's strength. When he was an angel, he could have vaporized it with a single touch. Now he had to keep reminding himself that he was human, and not invincible. He shoved the God against a wall and reached for the stake. Unfortunately, one arm wasn't enough to hold the bastard in place. It broke loose and flew at Sam, managing to slice his arm open before Cas could launch himself at the creature and finish the job.
Sam insisted he was fine, and that it wasn't Castiel's fault, but the guilt was still there. Cas felt even more useless upon realizing that he couldn't heal Sam. It was a superficial wound, but no doubt still painful. He was supposed to protect the Winchesters, and he had failed.
So here he sat, cutting open his own arm. He had caused Sam pain; so he needed to cause himself pain. In the back of his mind he knew that his logic was flawed, but he didn't care. It restored balance in a way.
He was startled by a knock at the door. "Hey, Cas, Dean made burgers. You want one?"
"Sure," He called out, hurrying to clean up the bloody mess. He emerged from the bathroom minutes later, making his way to the kitchen. Sam and Dean were at the table, eating and laughing. He noticed Sam's bandaged arm, and observed with some relief that the younger Winchester didn't seem to be in pain.
"Hello," He greeted them. "How is your arm, Sam?"
"It's fine." Sam smiled reassuringly.
"Are you sure? I really am sorry-"
"Dude, it's fine. He's good." Dean rolled his eyes. "We've had worse."
"Still..."
"Shut up and eat, your burger is getting cold."
Cas tried to push the remorse from his mind, scratching at the cuts under his sleeve. He had already completed his penance. He need not feel guilty anymore.
After they finished eating, Sam filled the sink with hot, soapy water and proceeded to wash the dishes.
"Let me help," Cas offered, rolling up the sleeves of his trenchcoat. It was the least he could do.
"Thanks, Cas-WOAH, what the hell happened to you?"
Cas tilted his head in confusion before realizing that Sam was staring at his arms. Most of the cuts were scars, but there were a few fresh ones which were bandaged, including the one he had just made.
"Oh, this? It's nothing. I guess it is a bit hard to look at, my apologies." He rolled his sleeves back down, face burning with embarrassment. His body was scarred and ugly. "I can still dry the dishes if you'd like."
"No, forget about the dishes..." Sam was already drying his hands off and reaching for Castiel's sleeves. "Let me look at these, did the God do this to you?"
"No, I did them to myself." Cas said, matter-of-factly.
"You...you what?"
"I cut myself." Cas was surprised by Sam's reaction. Why was he upset?
"On purpose?" Sam's hazel eyes were wide and filled with concern.
"Well, yes."
"You can't do that."
"Why not?" Castiel asked, pulling his arms away from Sam. He was confused.
"You just-you can't!"
"I don't understand."
"I'm having a hard time understanding too. Why the hell would you do this to yourself?"
"It depends. Sometimes it's to punish myself. But most of the time it's because it helps me."
"Jesus, Cas...you don't need to punish yourself, haven't you been through enough? And how does this help? Doesn't it hurt?"
"Yes, it does hurt. But that's the point. Pain is so interesting. When I cut myself, I don't even think about everything else that troubles me. It's an unusual phenomenon."
Sam shook his head in disbelief. "You have to stop."
"Why?"
"You're gonna kill yourself!"
Cas blinked. "No...If I was doing this with the intention of dying, I would be making vertical cuts along my Ulnar artery. These are all horizontal. See?" He pulled his sleeve up slightly to show Sam.
The younger Winchester swallowed hard, feeling sick. "What if you cut too deep?"
"It's extremely hard to die from this method of self-mutilation, no matter how deep I cut. I could always call you or Dean for help."
"That's not the point. Sit." He gestured to the table. "Don't move. I'm getting Dean."
"Why..?"
Sam left without answering, leaving Cas alone and confused. Sam's extreme reaction was unexpected to say the least. Why was he going to tell Dean? It would only upset him as well.
Cas sighed. He really was bad at being human.
