She stays behind while Edelgard selects and attacks her victim, as does Hubert. This is something that Edelgard requests of them, and something that Hubert has always done. She doesn't want them to see her in the act of killing someone, which is understandable, and by the time it's all said and done, she has the victim face down on the ground, so that Byleth cannot see their face.
Soon enough, she will see them on the news; there will be no way to avoid that.
She doesn't know if Edelgard has a particular method for selecting her victims, or if it is completely random, and she doesn't ask or try to think about it. Knowing those things won't actually change her feelings for her friend, and knowing that she is blinded by her feelings doesn't change anything about how she views it. Ignorance is bliss, or so they say, and if she's going to take a stance, she is going to take the same stance that Hubert takes.
She watches as Edelgard looks up, blood dripping from her face, and she is beautiful and terrifying. Something shifts when they make eye contact, or at least, it feels that way to Byleth, in a way that she cannot fully describe. But she feels like something shifts, and she can't look away, until Hubert walks past her, and she looks to him then, and the way he looks at Edelgard. Sensing her eyes on him, he looks back to her, making eye contact for just a second before turning his attention back to Edelgard. It's time to help her drain the body dry, saving enough for later, so that she won't have to do this for another couple weeks or so.
None of them speak as this goes on, but Byleth still feels as though things have changed. There is something different in the air, even after they've abandoned the scene, even when they're in the car.
Edelgard is the first one to break the silence, saying, "So, terrified of me yet?"
"I'm not," Byleth says simply.
"You've taken all of this pretty well. I can't imagine there are many people who wouldn't try to run away from the beginning, but especially not after that."
"I'm not going to run away," she replies, and Edelgard smiles, saying nothing else. Hubert doesn't weigh in on the conversation, but Byleth notices that he seems close to smiling as well.
~X~
Once they're back at Edelgard's house and settled in for the night, excess blood stored away, Edelgard seems eager to talk about pretty much anything else that she can. Mostly, they talk about school and how things have been with that, before moving on to the party and commenting on who they saw there, their costumes, what they were doing, and so on.
"And of course we couldn't escape Ferdinand," she says, "which I should have expected, all things considered, but I'd really hoped he might be distracted. As if we'd ever be that lucky."
"He seemed pretty excited to get to see you," Byleth replies, holding back laughter at the look that crosses Edelgard's face.
"Excited to pester me, sure! I can only imagine what was running through his head, or how he thought he could use whatever we talked about at a party to defeat me," she says with a scowl. "He's probably already planning his campaign for senior year, so maybe he was hoping I would do something to embarrass myself so he could use it against me, like a crooked politician. Or maybe he was going to challenge me to some kind of contest, so everyone else could judge 'once and for, who the best of us is'!" She finishes her sentence doing quotation marks with her fingers, and speaking in a voice mocking Ferdinand's.
"What a lovely impression," Hubert teases. "And it would not surprise me in the least if that was Ferdinand's aim."
"Maybe, but I think he was happy to see all of us," says Byleth, laughing along with them. "Sometimes I think he might just want to be friends."
"Hm, well, he could go about it a number of other ways," Edelgard says, dismissing the topic entirely.
As they continue to talk about the party, the subject of the vampire costumes eventually comes up, as Byleth was sure it would, and the topic turns grim from that point on. Edelgard apologizes, saying, "I know I have no right to be so offended, it's not as if anyone knows what it's like, but...even so, if they did know...well, first of all, they'd be terrified of me, but beyond that...I don't know what I'm trying to say."
"No one else can really understand what you're going through. It's understandable to be frustrated," Hubert reassures her.
"Even I hardly know what I'm going through," she says, more to herself than either of them, but Byleth decides to speak up then.
"I...I know that there's no way to know, but...there are things I've heard before, about...well." Somehow, saying the word 'vampire' out loud feels strange at this point. "There are legends that say, if you were to kill the one who turned you…" Byleth trails off, feeling ridiculous for suggesting it, but neither Edelgard or Hubert scold her or make fun of her for it.
"Truth be told, I've considered it," Edelgard finally replies. "But I'm not so sure that's really true, and even if it were, well...I don't even know where to find them. I don't even know who turned me, out of the three of them, though, if I'm being honest...I would probably want to kill them, all three of them, either way. I just don't know if it would do any good. Hell, I don't even know if it was one of them who turned me, or if there was someone else, who wasn't there when I woke up."
"I see," Byleth says.
"I appreciate you looking into it for me," she says. "Actually, maybe going out for revenge isn't a bad idea. Even if it doesn't turn me back, I won't know until I try."
"You wouldn't alone. I don't know what use I'd have, but you know that I'll support you however I can," Hubert says.
"So will I," Byleth agrees, surprising herself with how little hesitation she has, signing herself up to fight vampires. But it feels right, and she knows that she has no other choice. She's known them for such a short time, but already, she's closer to them than she's ever been to anyone else, and wherever Hubert and Edelgard go, she knows that she wants to follow.
"You...both of you...I don't know what I'd do without you," Edelgard says, and it looks as if she might be tearing up. "I know I've said that to you a million times before, Hubert, but...Byleth, even though we just met at the beginning of the year, I…you're so important to me, I don't know…"
"I feel the same way. About both of you. I don't really know how to explain it, I just know-" Byleth doesn't have a chance to finish her sentence.
She doesn't have a chance to finish her sentence, because Edelgard, who watches her intently as she speaks, suddenly lunges forward, pressing her lips to Byleth's, effectively silencing her. And all Byleth can do is relax into the kiss, until Edelgard pulls back, looking to her with a shy expression.
Hubert stands up then, saying, "I'll...give you two some privacy," but Byleth, emboldened by the kiss from Edelgard, will have none of that. She stands as well, stopping him in his tracks so that she can kiss him as well, stunning him completely.
The next thing she knows, all three are piled up together, kissing each other again and again, not sure who she kisses last or will kiss next.
