Their hearts beat calmly in their chest; by now they dealt with a demon as easily as they would a kitten. It had become easy for them, second nature they would call it. There were no feelings of remorse as they restrained the body; it was currently occupied by a beast, after all. And it wouldn't think twice about killing both of the brothers in an instant; so no, it's comfort wasn't really at the forefront of their minds.

It had taken control of the body of a young woman. If she hadn't been possessed by one of Satan's little followers, Dean would've considered taking her out. She had large green eyes that had glowered at them in the midst of their hunt. She had full lips that had pulled back in a snarl, baring her clenched teeth. But having your body inhabited by another creature came with some consequences; her hair was greasy and her eyes were bloodshot. Battle scars marked her body; her once smooth skin was now mottled with burns and scratches. The demon inhabitant had put up a good fight with the brothers in the beginning. Lucky for them, they had the experience of hundreds of encounters with demons under their belt.

However, the girl's appearance was probably the last thing she would be worried about once the demon was cast out of her body. Lord knows what it had made its vessel do.

But she wouldn't have to suffer for much longer. The demon could do no more harm; Dean was sure of it as he secured the body to the wooden chair. It wasn't mature, but the ties were tight and if that wouldn't do, there was still the ring of salt keeping the demon contained. As Dean carefully stepped around the ring, he felt confidant in his safety. It would be sitting there for as long as they said so.

They weren't sure when it would come to when a low sound emanated from the girl's throat. Eyes fluttering open, her head began to loll on her shoulders. And then she began to jerk on her bonds. Her frustration became increasingly evident as her body jerked in the chair, the wooden legs screeching against the floor. The sounds she was making was so longer the soft groans from moments before; now she growled and screeched, frustration turning to anger. Finally, she grew rigid, becoming silent as a mouse in a single second. Her wild eyes had narrowed, and they landed directly on Sam.

The girl probably had a beautiful voice, but when the demon spoke, it made their skin crawl. It was twisted and manipulated. It was evil.

"Now, what do the Winchester boys want with little ol' me?" It drawled, her lips turning up in an ugly smile. There was blood on her teeth and staining her lips. It belonged to the girl's body, the blood that still stained her face. But it wouldn't rest until it had a taste of the Winchesters too.

Dean silently thought about how good it would feel to simply take the bitch out. The way it was looking at them. It made his skin crawl. The feeling of being out of his depth began to naw at his subconscious, which was ridiculous. This was his territory, what he was born to do. But this felt terribly wrong.

There was a reason why their usual routine was kill 'em and go. This time, however, they were trying something new.

"You know who we are," Sam replied, his voice husky as the thrill of the job rushed through his veins. "You know why you're here."

The demon laughed. "Please, enlighten me." Her fingers dug into the arms of the chair, the only sign of its agitation. "Why am I still alive?"

"You're gonna be a part of our little experiment," Dean intervened. His steps were slow and the soft thumping sound resonated throughout the small bunker. Her head tilted, watching him as he walked towards her.

So many wonderful things she had heard about the Winchesters. Hopefully, they wouldn't disappoint. Let them torture her, let them do their worst. She had endured decades of torture, had experienced the worst torture imaginable as she rot in Hell. Anything they did to her would be child's play.

While they had their fun, she would have hers. Her body may have been restrained but her eyes worked perfectly fine; she would observe them, learn them, learn their weaknesses and their strengths. And then she would break free. And then... she would crush them.

"Experiment?" She parroted, playing the part that they had given her. The naive prisoner.

The term 'experiment' certainly had ominous tones to it.

"There was a man," Sam explained, walking into her line of sight, "that believed a demon could be purified and once again have its humanity. We think he was successful. Now we are doing our own studies."

His voice was softer than his brother's, not as brash. He stepped up next to Dean, towering over him. The brothers were clearly very different inside and out. She was starting to piece them together easily. Soon, she would be able to read them like an open book.

She scoffed. "That's ridiculous. Besides, don't I have a say in this?" She could get used to this, ruffling their feathers, seeing what made them tick. She wasn't surprised when the shorter one scoffed at her coy response.

Dean's reply was quick and gruff and expected. "No."

Leaving Dean's side, Sam began to stride across the room, out of its line of sight. Trying to remain impassive, she tried to peer after him, see what he was up to.

Pushed up against the wall was an old, dusty table that probably couldn't hold much weight any more. It looked unstable enough just sitting there, but Sam moved towards it with determination and reached out for the object that was resting on the table top.

She could hardly see it from where she was sitting but when he held it up, the light shone through the glass, illuminating the syringe. The long needle glistened as he pointed it up, inspecting the drop of blood that oozed from the tip.

After hours of observation and blood injections, they left her alone for awhile, down the cold cellar. Trying to turn a demon innocent again was bound to be hard work but at least they had an angel on their side.

"Have you made any progress?" Castiel asked when he finally arrived for the show.

Dean glanced over his shoulder, looking at his brother. Back in the cellar, Sam was leaning against the shabby table, gently flicking the pages of an old book. Beside him on the table was laid the syringe. Dean grimaced at the sight of the threatening needle; he was just glad he wouldn't be one the receiving end of it.

"Not much," Dean admitted. "We got a name though. Apparently, she was Eleanor Atherton. We kinda figured, I don't know, if she revealed that old piece of herself then we might be able to connect her more to her humanity. Couldn't hurt to try. Anything helps at this point. She's strange, man, even for a demon. It's like she enjoys this-"

"Did you say Atherton?" Cas cut him off, having not heard a single word since the name was uttered. He hadn't heard that name in centuries, but he had no trouble remembering it. It had echoed in his mind everyday.

It couldn't be her, a small voice in his head thought. What were the chances of stumbling across her like this? But Castiel had spent centuries searching. Perhaps this was only a matter of time.

Pushing past Dean without an explanation, Cas moved towards her, his vessels heart hammering in his chest. Both he and Eleanor wore new faces now but it didn't matter. If it was her, he would know.

Brow furrowed in confusion, Dean watched as Cas stepped towards the girl, inspecting her with his intense gaze, looking for something.

Apparently, he found it. Cas' face relaxed in resignation as he murmured, "So it is you."

Sam looked up from his book, frozen as he tried to catch up on what was happening in front of him. Dean couldn't have explained anything either. Now, they were both on the outside looking in.

"Well, look who decided to show," it said, her head slowly tilting to the side, her voice heavy with marvel and intrigue. "It's been a long time, Castiel."