"What is your relationship with Rin?" Archer's master asked him once, and he lost his balance in shock.
He has been careful not to show the slightest interest in the black haired hacker. She may look like her, even act like her, but she is not his Rin. The girl he idolised is long dead and gone. All that remains of her is the faint trace of her mana left in the pendant he carries with him.
He removes it from his pocket and runs his thumb over the smooth lines of the jewel. He hears a sharp intake of breath. Rin is standing at the foot of the bed, eyeing the stone longingly. "That gem..." Archer pockets it again. "It is part of my legend," he lies. She wavers a moment before she answers in a disappointed voice, "I see."
"Well then," she says in her usual voice. "Before we get started, I'll need a minute to prepare." Archer eyes her pointedly as she sits next to him. "Of course."
She is not his Rin, but as he watches slender fingers trace down pale legs to remove her stockings, he lets himself imagine that she is. It's an easy illusion to maintain. She already looks the part.
Then there is a noise at the door, and a familiar mana signature. Archer pales. His master is trying to peep.
Rin doesn't seem to notice. Archer clears his throat and puts on his best bored-sounding voice. "You know the procedure for a temporary contract?"
Rin nods. "Okay then," he says, his hands dropping to his pants. "Let's just get this over with."
"What in the...?" The hacker's face flushes. "How can you be so open to this?! Wait a second, how in the hell do you know so much about thaumaturgy in the first place?" She demands. He smirks at her.
The door creaks, loudly this time. Rin whips her head around, poising herself to attack. "What in the-" she begins, and then realisation dawns on her face.
"Hakuno, don't tell me you were peeking in?!" Before his master can confess, the door slams shut. "I told you to stay out!" Rin yells in his master's direction. "If you peek in again, I swear I'll wipe every last memory of yours!"
Archer chuckles, and then she turns her ire to him. "What are you laughing at?" She huffs. His Rin always did look cute when she was angry. He hooks a finger beneath her chin, and before she can protest, he kisses her. Rin makes a surprised noise against his mouth, but then she sinks into the kiss.
"I thought you wanted to just get this over with?" She whispers when they part. He shrugs. "If that's what you'd prefer." He doesn't want to seem too eager, and if she's as much like his Rin as she pretends to be-
"Hmph. I am doing you a favour."
He tries not to smile. "That's true. I suppose I should give you something in return then?"
He is too weak to face an enemy servant, but Rin is small and lithe, so it's no trouble to shift her beneath him on the bed. "Hey!" She says, as his hands slip underneath her shirt. "What are you doing?" He cups her breasts, his fingers darting beneath the fabric of her bra to brush against her nipples.
He allows himself a grin as he answers her, "I thought it was obvious." Rin's blush deepens. "Idiot! That's not what I meant! You can't just touch a girl like that...!" He takes one nipple between a finger and thumb, and pinches gently. "Are you telling me to stop?" He asks, with one eyebrow raised. Rin bites her lip. Her cheeks are dyed scarlet. "N-no."
Rin's back arches under his touch as he bends down to press kisses to her neck. She hisses when his teeth drag across her skin, and red marks bloom where he sucks and nips. He makes his way up along her jaw and closes his lips around her earlobe, tugging until she makes a keening noise. Her arms curl around him, her nails digging in just beneath his shoulders and raking down the side of his body.
He sits up to peel off his shirt and overcoat, and beneath him Rin hurriedly removes her own shirt. Her hands fumble at the zip of her skirt, and Archer gently pushes them aside and removes it himself. He runs his eyes over her almost bare body in slow appraisal. He'd thought about Rin's body many times, but not even the best of his fantasies could compare.
"You're beautiful," he says, before he can stop himself. Rin looks at him like a deer in the headlights. "H-huh?! Don't say stuff like that all of a sudden..." She leans forward and awkwardly tries to cover herself with her hands, but Archer's fingers resting on her arm stops her. He shakes his head. "I want to see you." Slowly, Rin lies back into the bed. "Fine," she says. "Have it your way." He does.
Her legs tremble slightly as he slides her underwear off, and she fidgets nervously when his fingers trace patterns over her legs. There is a gasp when he ducks to plant kisses along her thighs, and she makes a wonderful sound when his tongue licks down her centre. Her whole body shudders at the sensation. He darts his tongue out again, aiming for something different this time, and when her hips twitch in response he knows he's found it. Rin whines in a needy way as he continues, her hands gripping his short hair firmly. He probes her gently with the tip of his finger, and when she doesn't object, he slides one inside her, then two, and suddenly she's moaning his name between everything else.
He quickens his pace, his fingers pumping with ease, and Rin grinding her hips against his mouth. He can feel the heels of her feet on his shoulder blades. Her body tenses as she comes, her head pressed back into the pillow and her eyes closed. Archer plants wet kisses on her belly before he pulls away. His thumb strokes the skin beneath her breast as he waits for her to regain her composure.
She opens one eye to look at him. "I hope you're not expecting me to reciprocate."
He can't help but chuckle. "Of course not, Rin."
"Good." Her other eye opens, and her gaze travels down his body. She frowns disapprovingly when she sees his pants. "Well, get rid of all that."
He doesn't hesitate, and Rin arches an eyebrow critically when she sees what lies beneath. She opens her mouth to say something, but Archer decides that whatever it is, it's probably best for his ego if he doesn't hear it, so he kisses her before she can get the words out. His hand cups her cheek and she deepens the kiss, her hands finding his chest and exploring the hard muscles. They don't break the kiss until Rin is out of breath.
"Archer?" She says, and looks up at him shyly. It's a rare sight. "You'll be gentle, right?"
For a moment he's too stunned to reply. The thought that she hasn't done this before never even occurred to him. He smiles gently, and brushes a loose hair back from her sticky forehead. "Of course I will." He says, and plants a kiss above her brow.
Rin takes a deep breath, and then reaches out to touch him. She finds his skin surprisingly soft. He twitches in response, and she can feel him growing hard under her fingers. She strokes him slowly, almost hesitantly, and Archer resists the urge to thrust forward into her hand. They stay like that until Archer brushes her hand away and says, "That will do, Rin."
At his instruction, she relaxes on the bed, her legs slightly apart. Archer enters her slowly, watching her face for any traces of pain. He buries himself in her to the hilt and pauses, letting out a heavy sigh. It's hard to remember this Rin is made up of ones and zeroes when she's tight and hot and wet beneath him. her hips jerk forward, and Archer starts to move inside her again, building up the pace. Rin hums in approval.
He pulls her body closer as he thrusts, his hands finding purchase on her hips. Her flushed chest presses against his, and her lips meet his in a messy kiss. She starts to meet his thrusts, moaning into his mouth, and he starts to feel the build up to his release. One of his hands dips between her legs, his fingers pressing against her in a way that makes her mewl. As her second orgasm crests, she clenches around him, and he comes with his face buried in her neck.
They collapse onto the bed of the nurse's office, breathing heavily. Rin curls into him, and he wraps an arm around her protectively. For some time, they just lie there in silence. It's Rin who eventually breaks it.
"I don't expect you to get in trouble like this again or anything, but if it does happen, I'm not teaching Hakuno how to do this."
Archer lets out a dry chuckle. "I wouldn't have it any other way."