Hey there. I just wanted to say that this is an AU, so I'm not really following the storyline, but the two things to know is that the brothers live in the bunker at this point, and Adam does not exist in this universe. Hope you enjoy.
"What?" Cassie spluttered. "That's ridiculous!" Cas ignored her outburst and continued,
"Your mother, Kaitlyn, had a brief relationship with John Winchester directly prior to your birth, and Remiel explained to me that when Kaitlyn found out and told John, he asked Adrian to look out for her, as she lived in his vicinity. It was during that period they fell in love, and he raised you as his own. However, John Winchester is your biological father." Cassie felt as though her entire world had been knocked off its axis, and the brothers didn't look much better.
"Did…did dad know that she was part-angel?" Dean finally got out.
"No," Castiel answered. "Based on what Remiel told me, none of them even knew of the existence of angels." Dean released a deep sigh and ran his hand through his hair, his racing thoughts apparent.
"And you're just now telling us about this?" Sam finally spoke up, addressing Cas. His eyebrows were furrowed in anger. He glanced at Cassie who appeared to react similarly to Dean. That's when it struck Sam. She looked familiar because she looked like them. She seemed to have gotten her physique from her mother, but her hair color was almost identical to his own, and her eyes were the same shade of green as his brother's. Sister, he thought, she's our sister. The "half" part didn't really matter to him; in his mind, she was family, and you can't be half a family member.
"As I said earlier, I was unaware of it myself until a few weeks ago, and I wanted to take time to verify Remiel's claim and see how the child was," the angel answered calmly.
"Not a child," Cassie interjected seemingly on autopilot, as she still looked to be in a slight stupor.
"I can't believe dad never even mentioned this to us," Dean said to no one in particular, hints of anger creeping into his voice as well. "Do you ever remember meeting him?" he asked Cassie. She looked up at him and shook her head.
"No, I only remember my dad telling me about their hunts. He mentioned you guys a lot too. Maybe he was giving me as much a connection as possible; he thought very highly of John from what I recall, though he never agreed with his kick for vengeance." She smiled softly at the thought of her dad still trying to give her a connection to her biological father even though John never seemed to show interest. That didn't even really bother her if she was honest. She never knew John, so how could she be mad at him for not wanting to know her? She just didn't feel much of a connection. However, she could tell by the brother's – or, her brother's – faces that they were upset with John.
"From what I understand, John only knew of Cassie through Adrian. They never met, and when Adrian passed, John did not come back," Castiel said.
"Wait," Dean spat. "Dad knew that Cassie was holed up in an orphanage and never went to get her?" He whipped his head toward Cassie, "If we had known you existed, Sam and I would have been there, okay?" Cassie had no doubt that was true, and she felt the need to assure the brothers that she was not upset.
"Sam, Dean," she made eye contact with them both before continuing, "I'm still processing all of this, but I'm a champ at compartmentalizing, so I'll be fine. But you need to know, I am not upset with either of you or John for that matter. You guys didn't know, and based on what my dad said about him and how much he cared about his kids, I'm sure he thought not being in my life was what was best for me. Besides, I got lucky. My dad was amazing for the time that I was with him, and I landed in a great orphanage; they looked after me and helped me find schools that could handle my potential. So, go easy on your father. Don't ruin his memory over me," she pleaded with them. They both looked slightly appeased, though she could still see some anger harboring in their eyes.
Sam scoffed, "I think you might just be the most mature person I've ever met." He was impressed by Cassie's ability to take this in stride.
"Yeah, are you sure she's got Winchester blood in her, Cas?" Dean questioned sarcastically.
"Of course I am, Dean. That's what this entire conversation has been about," Cas answered confusedly. All three sibling pulled an identical face, and the angel was struck by the resemblance.
"Alright," Dean clapped his hands, "now that the family's all back together, let's get back to the crazy angel-loving demon." He nods at Cassie with a small smirk, still warming up to the idea of her as part of the family. However, he can't deny the connection he feels even in just the 20 minutes he's known her. She blushes before glancing down at her lap, obviously also still warming to the idea.
"To answers Sam's question about the protection spell from earlier, because it was comprised of a portion of Remiel's grace, when he died, the protection spell died along with it, which is probably how the demon was able to track down Cassie and her male non-companion," Cas said. Both brothers looked to their newly-found sister for an explanation. Cassie let out a load grown before explaining what had happened with Jake and his poker match. Sam and Dean still looked confused.
"How would your ex even have authority over your soul? I thought only the human whose soul they are receiving is allowed to gamble with it?" Sam voiced his inquiry.
"That is why I decided Cassie would be better off here. The demon after her soul has gone rogue, not respecting the very few rules Crowley has established for his demons in hell, which makes him especially dangerous. I've tried contacting Crowley, but he can't 'fit me in,'" Cas said with as much sass as an angel could generate. Cassie had gone slightly pale at his statement, not even concerned about who this Crowley character was but worried about what a demon with an eon-long obsession could do to her and the brothers who were taking her in so willingly. Sam noticed and gently reached to pat her shoulder, giving her a look of understanding.
"I cannot cast the same protection spell as Remiel, but I can perform a sigil marking, as I did for you and Dean. That should make it very difficult for the demon to her," Cas continued. The brothers shared a look with each other. Cassie just winced, using the freshly-downloaded angel-information cache in her brain to understand what that would entail. She let out a huff of annoyance because she knew it was the best option. Her eyes met Castiel's.
"I always thought my rib bones were too plain anyways," she said sarcastically. Cas just gave her a sympathetic look.
"Before we start frying any ribcages, can you explain why she needs to stay here if you're cloaking her anyway?" Dean asked. He looked at Cassie. "Nothing against you, we'd like to get to know you, but anyone who hangs with us usually ends up in the ground," he stated, his eyes darkening. She offered him a small sad smile before turning to Cas, also questioning his decision.
"As you both know," Cas began, looking to both brothers, "I have to go to heaven to help keep it from descending into complete madness, so I won't be on call—"
"Wait," Dean interrupted, pretending to look slightly offended, "Are you saying we're too clingy for you, Cas?" He let out a surprised laugh. Cas just scowled at him before continuing.
"As I was saying, I won't be as accessible to you if you are injured, and, while Cassie cannot offer immediate healing, she knows stitching techniques that don't involve cheap liquor, and she's quite skilled at emergency medicine." Cassie nodded absentmindedly while thinking through what the angel had said. She knew she would feel more comfortable staying in their home if she had a purpose, and while an in-home nurse wasn't exactly her first career choice, at least she would have a chance to keep practicing medicine while all this demon stuff was cleared up. She would also be able to pay Sam and Dean back for their hospitality. From what she knew of them, they were decent men who deserved someone looking out for their well-being. However, she knew this job might get tough when it came to getting them to admit when they were in pain. She'd grown up around hunters and was more than familiar with the injuries they sustained and their stubbornness to ignore them. She went to med school to help people, and that's exactly what she'd do. This would be good for her.
"You dragged a girl out of medical school to become our on-call doctor?" Sam said, seeming aggravated. The situation reminded him of his own struggle to create a normal life. Before Castiel could answer, Cassie cut in.
"I'll do it!" She exclaimed. All three men turned to look at her, obviously surprised by her exuberance. "Look," she explained. "I began studying medicine because I want to help people. I use to help patch my dad up all the time, so I know what kind of injuries to prepare for. And, I want to repay you for the protection and the work I know you guys do. My dad made sure I knew you were good men, and you deserve someone looking out for you." There was no waver in her voice as she looked both brothers in the eye. Their eyes softened for a moment, and she received a nod from each.
"Alright, now that that's settled, I will retrieve Cassie's belongings before I do the marking. Also, the demon tracking her is, to my knowledge, unaware of her connection to the Winchesters, so he won't know to look for either of you, Sam and Dean. I'm not sure how long it will take for me to return from heaven, but we will deal with the demon then." He vanished before anyone could a word in edgewise.