A/N: This is my first ever Supernatural story, please bare with me as I haven't written anything in ages due to a virus eating my files and putting my off writing for a while. Feel free to point out any mistakes; this story is unbeta-ed. Constructive criticism is also welcomed here. =D

Summary: This is my take on what happens after the Season 6 finale, but I highly doubt that this is what will actually happen. This was just a plot bunny that wouldn't leave me alone. What would happen if the memories of Hell affected Sam in a way nobody expected? Limp!hurt!Sam with slightly hurt but comforting Dean. Enjoy. =)

Disclaimer: I do not own Supernatural, nor do I own any characters that you recognise within this story.

The Similarity Between Souls

By Eleanor Jane Farrell

Sam, Bobby and Dean stood horrified at Castiel's cold expression. The former angel was completely emotionless and blank, enforcing his new status as God, but that didn't necessarily mean he'd be good at his new job, or if it was even Cas standing in front of them. The hunters were at a lost for what to do.

When Dean had first met Cas, his features had been just as blank but not without sympathy for humankind; he hadn't quite figured out how to interact with people. With a little help from Sam and Dean, he had managed to learn about human customs, routines and most importantly: friendship. This wasn't the friend that Sam and Dean had gotten used to. This wasn't the angel that they had gone so far as to say that he like family to them, like a brother. No, the Purgatory souls had eaten their way through their friend and ripped out his personality, the very person he used to be…but maybe there's more to it than that.

Sam, Dean and Bobby shared a few alarmed looks whilst Castiel was waiting for an answer from them: "So you will bow down and profess your love unto me, your Lord. Or I shall destroy you." But they couldn't bow down, not to the thing in front of them, because whatever it was, it definitely wasn't Cas anymore. Nobody moved, they were too busy standing stock-still to avoid catching Castiel's attention too soon. Sam was the first to disrupt the stillness; a pained expression crossed his face as he brought his hand to his temple to massage his aching head in hope that it would assuage some of the agony as Hell's flames licked at his mind. He hadn't had time to even think about Hell in his rush to help Dean and Bobby, but now he had time he couldn't hold back and suppress his memories from the Cage, and what excruciating memories they were.

A sudden wave of overwhelming pain forced him to his knees, both of his hands now clutched at his head, he wasn't even sure when the other hand had reached up to join his first. The burning within his skull felt familiar as well as new, it took Sam a while to place it and then it hit him: Demon blood. The Hell memories were akin to the feeling of power that he had once consuming Demon blood. Sam could feel the pull of his Demonic powers and he embraced them - it seemed like they could use all the help they could get. A slight feeling of regret entered his heart when he thought of Dean; he didn't like Sam using his powers and would probably assume Sam had snacked on a Demon on the way here, but Sam could straighten all this out with Dean afterwards. For now, however, Sam could feel the souls residing within Jimmy Novak. He could also feel something new, but oh so familiar. Sam wasn't sure but if he had to guess he'd say it was Castiel's Grace calling out to him, screaming for help. This was all the encouragement Sam needed; Cas was trapped somewhere within his own Vessel and whatever was in charge now had completely overpowered Cas.

Sam took a steadying breath and spied the look of concern that Dean was shooting his way but unable to make his way over as the thing who had trapped Cas was standing in his way blocking his only pathway to his brother. Sam tried to smile at Dean to reassure him that everything would be okay, he's not sure but he thinks it comes across as more of a grimace. Sam slowly stumbled to his 6 foot plus height, closed his eyes and put his hand out in front of him to guide his powers. Sam felt the tug of his powers in his mind and concentrated on pulling the Purgatory souls out from within Cas. It actually surprised Sam a little that his powers were working, he'd never used them on anything but Demons and the fact that they worked on Purgatory souls frightened him. If he could exorcise and kill Demons and apparently exorcise Purgatory souls from Angels then what about human souls? He didn't want that kind of power but this little exercise proved to him them the souls from monsters and Demons were the same…so what about human souls, were they the same too? Sam's concentration wobbled a bit as his thoughts strayed and he was about to pay for that dearly.

The monster in front of Sam took advantage of Sam's distraction to throw him across the room. Sam groaned as he hit the white-tiled wall hard and flopped limply to the ground. A trail of blood had started to trickle down from his hairline from where his head had collided with the wall. He wasn't sure how much more abuse his head could take today: first Death's Wall came down leaving him with the agony that followed that, then there was the half-cocked try at exorcising Purgatory from Cas - which only added to the pounding in his head - and now he was pretty sure that his head should have exploded going by the excruciating pain that felt like Lucifer was personally living inside his brain torturing it, just like that time he…NO, STOP don't go there, Sam told himself. Now wasn't the time to wallow in his memories.

Sam looked up just in time to see Dean charge instinctively at the "Purgatory Monstrosity", Sam refused to call it Cas until the said Angel had his control back. Dean's move obviously wasn't going to work - he had acted rashly when he saw Sam flying across the room and couldn't stand there and do nothing - so it was no surprise when Dean was faced with the same treatment that Sam was. The already injured Dean was thrown into the wall under the staircase, his legs hitting the very same table he fell on when Crowley had telekinetically thrown him earlier when he and Raphael were trying to do their ritual. He grunted in pain when the wall jarred his already hurting arm. Bobby rushed to his side immediately, his eyes were wide with fear as the Cas-monster walked slowly towards them as if he had all of the time in the world.

The Cas-monster let out a small disappointed sigh, "You did not bow down to me, now I'll have to destroy you."

"No!" Sam called out from his place on the floor, an uneasy feeling settled in his stomach as Castiel's usually intense eyes found his. He whimpered when his ribs and heavy head resisted as he tried to pull himself up. He'd either bruised or broken his ribs and now they were protesting strongly at any movement at all. He was tired and aching and all he wanted to do was curl up, fall to sleep and never wake up again if this was what life was going to be without Death's Hell Wall, but of course, he couldn't leave Dean at the mercy of this monster who looked like their friend; he couldn't leave Cas trapped inside his own Vessel even though he brought it onto himself - after all, Sam needed a little help after he got himself addicted to Demon blood, so it was only fair that he helped his friend when the positions were reversed. Sam struggled to his feet for the second time that night and decided with grim determination that his powers will work this time but he needed a new method, his old one was too slow. Cas had billions upon billions of souls swimming around in his meat suit and up until now Sam had only had to exorcise one Demon at a time, the nearest he had ever gotten to a mass exorcism was when he was faced with Famine's Demons and even that wasn't that many compared to the massive task ahead of him.

Sam could feel his pronounced heartbeat against his aching ribcage and he trembled slightly when the Cas-monster headed his way, looking at Sam with mock pity. Sam shrank back slightly and tried to regain control over his breathing. I've got to do this, Sam repeated over and over in his head even though he just knew what he was about to do would be very painful, I've got to do this. Sam felt an urge to flee as the Cas-monster smirked at him as though he could read his mind. Sam looked over at Dean with regret-filled eyes, he wanted Dean to understand that he had to use his powers, it was the only way. The disappointment that Sam was expecting to be flashed his way was only a look of deep concern and understanding, and that look was all Sam needed to give him strength to do this, he even smiled slightly as he turned his attention back to the thing that help Cas captive.

"I'm not letting you take Cas away from us," he said softly before concentrating all of his power on him. This time Sam was determined not to give in to any distractions nor was he going to give up, no matter how much it hurt. Sam gave it his all, he used more psychic energy than he did when he killed Alastair and Lilith combined, and more. The room lit up with the light that the souls emitted, it was just as bright as when they had first inhabited Cas. The Cas-monster struggled briefly amongst the onslaught of Sam's power.

Sam cried out in pain as intense agony seeped through him; forget his hurting head, the white-hot pain invaded all of his senses, it crawled down his spine, through his muscles and right down to his bones. He was so consumed by his pain that his didn't even notice the tears running down his cheeks or the blood coming from his nose. He was also oblivious to Dean calling out in panic or to Bobby's cursing. At some point his legs had buckled under him and Sam had found himself on the floor for the third time in a row, it was a testament as to how much pain his powers were causing him when he didn't even realise that the fall had knocked his broken ribs. Sam didn't open his eyes until he could feel the Cas-monster's power waning, that's when he felt the very familiar souls of Demons, about 50,000 of them…Cas had Demons inside of him too? Could this have also affected his behaviour, just like the Demon blood had once done to him? As soon as Sam had watched the final souls from Purgatory disappear into the wall which had Raphael's Vessel's guts splattered all over it, he focused his depleting energies onto the Demons residing within Cas. This was an easier task that Sam had done many of times but on a smaller scale. When he was finally satisfied that there was only the one being that belonged within Jimmy Novak, exhausted, Sam collapsed onto his side. He moaned in pain when he jolted his ribs again.

Cas watched Dean run to Sam's side from where he had fallen to the floor. The exorcism had drained him but he'd recover. He felt a overwhelming feeling of shame and guilt run through him. How could he ever fix what he had done to his friends? Dean was right about his plan all along, he wasn't strong enough to tackle the souls and he had Sam to thank for saving him. Cas watched as Dean gently picked Sam's shaking upper body up and laid it across his lap.

Sam laughed weakly and asked, "Did I do it?"

Dean smiled softly down at Sam and then looked at Castiel, his bright, blue eyes were suspiciously watery and held so much emotion that Dean had to look away. "Yeah. You did it." Dean's voice was gravelly but soft and loving. Mindful of his own and Sam's injuries, Dean shifted Sam up so his head was resting against his shoulder. Sam smiled widely then, showing his dimples.

"I did it! I really did it!" Sam smiled contently and then his suddenly shifted and looked at Dean, his eyes pleading with Dean to understand. "I didn't drink any Demon blood, Dean! I don't know how I used my powers, I don't-"

"Shhh," Dean interrupted Sam and just pulled him closer to his shoulders. "It's okay."

"Dean…" Cas chose Sam's silence as an opportunity to join the conversation. Dean cut him off with a sharp look.

"Don't, just don't," Dean replied harshly with barely contained anger.

"Dean," Sam said softly, "it wasn't his fault…the souls were controlling him."

"Yeah? What about before he got all nuked up, huh? What's his excuse for that?" Sam hissed as Dean's voice aggravated his migraine, Dean softened his voice, "Sorry. He pulled the Wall down before he did the ritual, Sam."

"He had Hell souls in him too, Dean, I think they made him act differently. I think the influenced his decisions, I mean, having 50,000 souls from Hell inside you wouldn't exactly make you think of cupcakes and candy." Sam chuckled mirthlessly, "Who knows what that'd do to an Angel, you know? I don't think it was his fault, man. I mean some of it might be but I don't know." Dean looked as though he was going to reply but he could see Sam's eyes drifting shut and just settled for cradling Sam closer to him.

Bobby, who'd been standing awkwardly in the background with his cap in his hands turned to Cas.

"Are you still juiced up or are you you again?" he asked gruffly.

"I'm me," Cas answered confidently. He pushed himself off the ground and looked mournfully at Sam and Dean. "I'm sorry," he said in a truly saddened tone. "I didn't know this would happen… You were right Dean…" he trailed off, unsure what to say next.

"Hurts," Sam whimpered and drew Dean's attention back to him. He screwed his eyes tightly shut, reached his hand up to his head and pressed hard against his skull near the dried blood from the cut in his hairline and then Sam laughed giddily before promptly passing out. Dean looked fondly at Sam whilst he gently ran his hand through Sam's soft hair. He quickly pulled his hand away however, once he remembered that he had an audience. Dean cleared his throat and made a move to lift his brother up.

Dean took pity on the sorry looking Angel and asked, "D'you think you could give us a hand Cas and zap us over to Bobby's?"

The thought of leaving his totalled baby behind pained him but Sam was his priority at the moment. Cas nodded slightly and pressed two fingers against Dean's and Bobby's foreheads and then they disappeared. Cas didn't follow them back and wouldn't return until they called.

Later at Singer Salvage, Sam will wake up to find that he couldn't remember Hell. It was as if Death's Wall had rebuilt itself, but that was impossible. Sam could still feel his powers within him and he could also feel an itch at the back of his mind…could it be possible that his psychic powers had built it's own Wall to protect him from Hell? Sam didn't finish that that line of though because he slipped back in to unconsciousness moments after. The next time he wakes he is greeted with a smiling Dean, a bowl of soup and medication for his aching head. All was well for now, and Dean would probably forgive Cas in time, but maybe Cas had to forgive himself first.

A/N: Please let me know what you thought. =)