This is my first attempt to justify a Faith/Giles pairing using context. I'm interested in seeing reactions to it to see if it's worth pursuing. It's taken up sometime during Season 8 of Buffy though it likely won't follow the storyline of it. It was just more convenient to see Faith and Giles alone in that period.
Giles got up in the middle of the night to pad across his flat to the bathroom. He paused when he saw a light in the living room and went to investigate. When he saw Faith asleep on the couch he relaxed and shook his head. He might never be used to having the Slayer living with him. He'd lived alone far too long. He stepped further into the room and gazed at her face, lit up with the soft light of the couch side lamp. She looked much more innocent in sleep than she did when she was awake. Her speech, for one thing, gave her away each and every time.
He turned to leave and heard her stir. "G?"
He paused and turned back. "S'nothing Faith. The light was on. I came to check on you. It's fine. Go back to sleep."
He turned and left the room and nothing more was said on the subject. He went into the bathroom and went about his business, thinking of the bizarre circumstances that brought he and Faith together. By all accounts and reckoning, she should have been with Buffy, the real one, training newbie Slayers how to use their powers for good and not evil. It wasn't her life and he knew it. She wasn't the good daughter like Buffy was. She carried her own agenda. So when he met up with her in London by accident, it wasn't much of a surprise.
One thing led to another and they ended up finding out they were pursuing the same nest of vampires. Once the task was done Faith expressed no interest in going back to the life of a teacher to incorporate herself into the Scoobies. Giles had no place there, either, and preferred to keep himself available to continue the good fight, one demon at a time. With such similar goals it had been only natural for him to ask her to stay on for a while so they could fight together. Watcher and Slayer, as it should be. And yet, somehow, not.
When he emerged from the bathroom after washing his hands he found the light still on and a very awake Slayer sitting on the couch, peering over the back of it waiting for him to emerge. He stopped in his tracks, a quizzical expression on his face while he looked at her. This was only the third day of their living arrangement and so far he was still not used to anyone there, let alone a girl who infuriated him when he couldn't predict what she was likely to do next. This was one of those times. Her brown eyes bore into his from across the room.
"Giles, why am I here? Why not your golden girl?" she asked softly.
"There is no 'golden girl', Faith. You and I have a similar goal, that's all."
"You always make me her substitute. I'm tired of being the stand in, G."
"You're no one's stand in, Faith."
He blinked. "What makes you her replacement, then?"
"She finally found the strength to stand on her own. You're here waiting for her to come back and found me instead. I'd say that makes me her replacement."
"Really? Then why am I here?"
"Because you want to hold on to the old ways. One demon at a time as it should be. I'm glad you're doing it."
"Because, Faith, you're holding onto the way it ought to be. Buffy opened the way to make all of the Slayers awake all the time. This will throw the entire world off balance. That sort of strength doesn't bode well for everyone. Some of the girls are bound to have moral compasses that don't quite face North."
"The old you, perhaps, but I suspect your going rogue was less about a lack of moral fiber and more the result of everyone in your life letting you down."
She scoffed. "Are you my therapist now, G?"
"Hardly. Still, I wonder what might have happened if you'd had a better Watcher."
"What's the point of that? Not even you wanted me. You had your precious Buffy."
"You weren't assigned to me, Faith. We had rules."
"Right, the rules. Did the rules include my Watcher running off? I mean, I was right under your nose the whole time, G, and you never wanted to be bothered with me."
She threw up arms up in the air, pacing a short distance away from him. With her back turned she heaved a long sigh and closed her eyes. She was older now. Not so old as him, of course, but older. She'd had a lot of time to sort things through on her own and he was right. Doing the job the way it was meant to be done, Watcher and Slayer, felt right. It felt better to her than trying to coach a bunch of girls into being warriors. Not everyone deserved that burden. Not everyone deserved that life.
"You think I'm stupid, Giles, I get it. Really, I do. If I were you I'd probably think the same thing of me. But I think it's funny you can think that when you can't even open your eyes and look around you! I always sided with you! I came back to that stinking pit of a town to try and help you because you wanted me to. And when you weren't busy pitting me against your precious Slayer you were wondering when I'd turn to the dark side. You never once asked if I was ok with any of it, or why I did it."
The Watcher was curious now, taking a step closer and staring at her with piercing jade eyes. "What are you talking about, Faith?" he managed to mutter, feeling more wide awake than he'd have liked at three am.
"You were so busy chasing after Buffy trying to be her hero, probably just as in love with her as everyone else was, that you never noticed you were mine. When I killed that man do you remember what you told me? You said I could be more that this didn't have to ruin my life. That it was ok to make a mistake and be a good person. I believed you. Not at the time but the longer I think about it. I wanted to be a better person because of you, Giles."
He softened somewhat, hearing that. "Faith, I wasn't trying to be anyone's hero and I certainly never entertained the idea of being in love with Buffy. That would be quite absurd. She was like a niece to me, rakish devil of a man that I am. And I had no desire to be your hero either, Faith. I'm not worthy of it. But you are right. You grew to be more than you were, more than I give you credit for, I'm afraid."
"Oh." She didn't know how to respond and they stood there looking at one another for long minutes without speaking. Finally the Slayer broke the silence again.
"Maybe I should leave." She suggested softly. Things were getting far too complicated in her book and complicated emotions meant goodbye Faith.
"Right, of course, leave just when someone expresses a desire to have you around." He couldn't hide the slight tone of disappointment and didn't bother to hide the plain disgust. "That's your MO, isn't it, Faith. Leaving just when someone might come round and care."
"You have no idea how I work, G."
"Oh, no? I should think I see things pretty clearly. You push people away the moment they get close to you just so you can stay in this self imposed exile of yours."
Her temper flared. "Guess we have that in common, don't we?"
"How do you mean? I loved Buffy, Willow, Xander and Dawn as my own family, moreso than the parents I have living no more than an hour from us."
"Really? Is that why you continued to abandon them time and time again when they needed you?"
Giles winced. "Buffy would never have learned what she was capable of if I'd stayed. You know that."
"Yeah, you came back long enough to throw her a bone so she could be reminded of what she was missing before you took off again."
They were toe to toe now, in the midst of the argument, daring each other to step up or back down which neither was capable of. Thrown into it, both would have rather died than admit defeat to the other.
"You really are stupid and arrogant, aren't you?" The Watcher asked softly. It seemed like life had switched now. Slayers were in abundance and Watchers were scarce. The irony wasn't lost on the man as he came closer to the Slayer. She glowered in his direction.
"I'm arrogant and stupid?"
"Yes! Bloody hell yes!" he threw his hands up in the air. "You envy the hell out of Buffy. You always have. You even went so far as to take over her body you wanted to be her so much and now you sit here and try to tout the merits of going solo as if that's going to make you better somehow."
She matched her eyes to his, sizing him up, staring at him, hating the words he said for the tiny amount of truth they held in them. "Says the man who spent his younger years trying out petty crime and making deals with demons just to escape his destiny. Who do you think you're fooling, G? You spent all those years as Ripper trying to make a name for yourself as a badass because you didn't want to go home and face your Daddy."
She sneered at him, her eyes burning with fire. Giles responded in kind, with a growl. "At least I actually am a badass. I don't have to pretend."
"I'm more of a badass than you can handle, G."
"Is that why you sleep with every creature willing? Sounds like overcompensation to me. You're still searching for that Daddy figure to substitute for your past."
"At least I can get laid. You wish you could have some of this."
"Why? So I can become just another statistic to you? I talked to Robin. He said he'd had better. I'd hate to be disappointed."
She slapped him. It hurt, stinging across his cheek as a warm seeping pain pushed down deeper. Without stopping to think he backhanded her back. Then his hands reached out to grab her by the shoulders. He pulled her to him and crushed her mouth with his, silencing anymore of their hateful words. He devoured her lips, his tongue playing over hers with some passion loosed in the midst of his anger. It wasn't about any sort of love or feeling between them but this intense need fueled by some force he couldn't explain. He groaned aloud as her body yielded against his and her mouth reciprocated what he was giving.
The air grew electric around them. Time seemed to stretch on forever, elastic, as they stood kissing with such a display of force and desire that Giles felt he might literally go weak at the knees. Everywhere he challenged her. At every point where he felt she ceded some ground she found a way to put herself ahead again. Their kissing stopped being about passion and turned slowly into a war of wills. It was, without a doubt, the most erotic thing he'd ever experienced in his life. This girl against him didn't cater to bullshit and didn't mask who she was or what she wanted and right now it was him.
Small sounds of desire leapt from her throat before she finally pulled herself away from him. She pushed him away and looked at the floor. He panted, placing a hand on his chest to feel his heart thundering in his chest. She was someone unlike anyone he'd ever met except, perhaps himself. They were remarkably similar creatures. He understood that now. "Why'd you stop?" he asked, heaving for breath.
"I'd hate for you to become a disappointed statistic whose only purpose in my bed is to be a pathetic attempt to satisfy my daddy issues."
He growled and turned his back on her. "You are singularly the most infuriating woman I have ever met in my entire life!" he shouted.
"Makes you hard just thinking about it, doesn't it?" she asked softly, her eyes sparkling with mischief.
In lieu of an answer he stormed out of the room and back into his bedroom. His body was on fire, every last ounce of his mind concentrating on the feel of her mouth crushed to his so hard he tasted blood. His or hers, he didn't know. Her parting words taunted him mercilessly and he pressed a pillow to his face to try and get them to stop. He did want her, so much so that he could barely stand it. And yes, it was her impulsiveness, her passion, her inner fire, that tongue and her wit, every single thing she possessed that made him want to strangle her were the same things that caused him to want her. He knew without asking that they'd be a brilliant match together, fire between them. She could be dark, so could he. She could be stubborn, he could be persistent.
He growled as his hand slipped down his body to do something he hadn't done since he was a school boy. He closed his eyes and remembered, savoring the thought of it on the tip of his tongue. Only a minute passed before he found release and he didn't realize how badly he'd wanted it. One could only be a professed celibate in the cause of duty for so long. Even though he'd reached his climax on his own he still wanted her. His body still burned with his old fire and fury. He thought he'd lost it when he put Ripper to bed. Not so, apparently. He lay in the dark a long time, mulling it over in his brain.