Disclaimer: Fate/Zero isn't mine, although I can understand your confusion, given the prevalence of Saber/Iri.
A/N: Have some plotless flangst (it's my real OTP, aha). AU ending of ep. 16, "The End of Honor".
By the Grace of Avalon
"Kiritsugu has left, hasn't he?"
Irisviel's voice is thin, almost lilting, and Saber glances at her sidelong in the brightening glow of the rising sun with the question already leaping from her lips. "Irisviel?"
And then, to her sudden, swelling horror, she watches the other woman sway; there is such grace in the motion, and she unfurls like a wave that has finally surrendered to the shore.
"Irisviel!" Saber shouts, panic edging its way into her tone, and she is quicker than gravity. Darting forward, she catches the Einzbern in her arms and almost immediately sinks to her knees, but even in the unfamiliar clutches of fear, she had the presence of mind to wonder why. It's not as if Irisviel is heavy; in fact, she feels too light, as if all her bones have become hollow. And it's not as if Saber is tired—she is weary, granted, from her triumphant battle with Caster and her duel with Lancer and, more so than either of those, she is weary from the disgraceful conduct and abhorrent espoused ideals of her own Master—but in that moment, when Irisviel's negligible weight taxes her arms, she loses all the strength in her formidable body.
She thuds to her knees on the cracked and bloodstained pavement, and everything about this moment hurts more than all the battles she's waged before, even more than the mortal blow she has circumvented back in Britain. Before, in the forest outside of the Einzbern Castle, when Irisviel lay unmoving and bleeding on the woodland floor, she had experienced a shade of this dread, but it is so much more pronounced now.
Now, it seems, she is much more acutely aware of what she stands to lose.
She calls the other woman's name again, gentle, insistent—Irisviel, Irisviel—but the homunculus fails to respond, hanging limply in the Servant's arms. Swallowing against the rising tide in her throat, Saber consults her memories, scanning for the responsible incident that would have rendered her Master's wife thusly. But she can remember no attacks, no strikes landed or blows cast astray, and unlike that time in the forest, there is no obvious evidence of injury, and Saber's touch does not seem to be calling her back to life.
Her fingers tighten on the delicate body, an uncontrollable spasm, but then she sets her jaw grimly and wills strength back into her muscles. Cradling Irisviel against her chest, she rises to her feet with minimal effort and walks around to the passenger side of the car, shifting the still body in her arms so that she can open the door. Once Irisviel is slumped in the seat—once Saber's questing fingers have confirmed a pulse, however intermittent and slow—she hurries to the driver's side and jams the key into the ignition, cranking it around with more violence than necessary, and she is hardly reassured by the growl of the engine coming to life.
As she glances through the windshield, she pauses for a moment, transfixed anew by the puddle of Lancer's self-shed blood and the mutilated corpses of his Masters. If Kiritsugu had just stayed out of it, if he had just trusted her, then none of this brutality would have happened; Lancer would have been defeated in an honorable knights' duel, and his Masters, rendered powerless, would have been permitted to leave unscathed.
But that is in the past now, just another thing that Saber cannot change.
Shifting the car into gear, she spins the wheel until it locks and smashes the accelerator to the floor.
Burdened once more by the weight in her heart more so than the weight in her arms, Saber jogs through the Japanese-style house, heedless of the cobwebs and dust that had so annoyed Irisviel upon their arrival, all too cognizant of the fact that, lest she act quickly, Irisviel might never have the chance to be annoyed again. She shoulders her way through the final sliding door, urging it aside with a forceful bump of her hips, and then she's running across the unkempt lawn and fumbling with the shed's doorknob.
Inside, it is cold and dark and musty, but the magic circle beckons where it is traced on the concrete floor, and Saber kneels at its edge and gently lowers Irisviel to its protection. The dull red lines flare to icy life as the homunculus makes contact, but despite being activated, it seems to have little effect on its host; Irisviel remains unconscious, but Saber does not know what else to do, so she elects to trust in the magic and the instincts that guided her here.
She sits back on her heels, and after a few moments, she shrugs out of her suit jacket, folds it several times, and eases it beneath Irisviel's head in a makeshift pillow.
It doesn't seem to do much, either, and Saber's hands roll into powerless fists.
From unsettling darkness—a darkness infused with glimpses of red and a steady drip-drip-drip—Irisviel rises to pale afternoon light. It's spilling through the open door of the shed, and it frosts Saber with its glow as she waits with her fists pressed into her thighs and a troubled pinch in her brow. When she sees Irisviel stir, though, relief flickers across her features.
"You're awake at last," she remarks, and she leans forward into the cold glow of the magic circle and extends a hand to help her up.
Irisviel smiles faintly, but even doing that drains her of energy, and the expression fades. "I am," she says softly instead. "Somewhat, anyway."
Saber's hand curls back, and a frown chases along her lips. "What happened? I know you are weak for…for whatever reason, but I did not realize it had become so bad." A note of reproach creeps into her tone as she continues, "You should have told me that you were not feeling well. I cannot protect you from threats that I do not even know are present."
Touched as she is by the Servant's concern, Irisviel does not immediately dispel it. "I appreciate that, but there are some things that even you can't protect me from; my destiny is such that you can only delay my death, not outright prevent it."
A muscle pulses in Saber's jaw, and something seems to crack behind her eyes. "I want to help," she insists at length. "Tell me how I can help you."
Irisviel gazes at her in silent consideration, and then she shifts her hand along the ground, reaching feebly towards the knight. Saber recognizes the gesture almost instantly and follows through, and the homunculus sighs as she feels Avalon activate and spread its restorative strength throughout her unnatural body, repairing damaged pathways and reconstructing others entirely. But it is still insufficient, and her eyes dim.
"It is not enough," she murmurs, not even aware she has lamented this aloud until Saber questions it.
"What is not enough?" she wonders, and she glances down at their joined hands and jumps to a conclusion. "How is my touch any help to you? It seemed to restore you in the forest after you were attacked by Kotomine Kirei, but I don't understand."
Irisviel offers another weak smile by way of apology. "Kiritsugu didn't want to tell you."
That sparks a familiar fire in Saber's eyes. "Far be it from a Servant to question the will of her Master," she all but spits, "but I heed his opinion very little, indeed, now that he has explained his true beliefs. His logic is patently absurd, and so whatever he may have instructed you in regards to me, I demand that you dismiss it."
The knight's blunt honesty and unwavering conviction hearten Irisviel, as it proves that Saber has strength enough to carry on fighting; she certainly, then, can handle hearing this. "You were summoned using Avalon as a catalyst," she explains. "But as you will have surmised from your troubles with Lancer, Avalon did not remain in your possession. I wanted Kiritsugu to take it, as he is your Master, and otherwise, I want him to live to fulfill his dream, but he made me take it instead, as a concession to my safety."
"If he would flaunt you on the battlefield, even with me as your shield, I should hope he would do as much," Saber sneers, but then she sobers, her brow knitting anew. "If you have Excalibur's scabbard, this explains the incident outside Einzbern Castle, as well as what has transpired today. I worry, though," she adds, "because your condition back then should have been the more severe of the two, yet you seem weaker now than ever, even with Avalon's supplement."
Irisviel manages to twitch her shoulders in something like a shrug. "Avalon might be able to heal any wound, but I'm not exactly wounded, am I?"
"That could be a barrier," Saber concedes, "but the scabbard is powered by my mana. To increase its effectiveness, I increase the mana output. Now that I know you have it, I should be able to accomplish such a task with ease."
But Irisviel shakes her head. "I don't see how, my knight," she denies gently. "I am not your Master. There is no flow of mana between us, no sharing of magic circuits. I will have to make do with what mana Avalon receives automatically from your proximity, for which I am very grateful," she hastens to add.
Her frown deepening, Saber contemplates their joined hands again. After a minute, and with slow, purposeful movements, she releases her hold, peels off her glove, and laces their fingers back together. Her skin is callused and subtly rough against the unworn silk of Irisviel's, but that stops neither of them from gripping more tightly.
Even so, and even knowing that she'd be blushing if her blood had the strength to rush to her cheeks, Irisviel wonders, "What're you doing?"
"It seems to me," Saber says delicately, like someone treading on thawing ice, "that my mana is being transferred via direct contact. Therefore, perhaps, the more direct or widespread the contact, the more mana you will receive."
The Einzbern opens her mouth to refute such a hypothesis, but she cannot, for it seems to her that there is warmth here not just generated by Saber's hand, a warmth that exists under her skin and sinks down into her bones. The side effects of this tactic are also too wonderful to ignore or hope to resist, and Irisviel agrees with the slightest rasp in her voice, "I think it's working, so…maybe if you…lie next to me, it will…" She trails off, though, her tongue too thick to continue articulating such glances of the truth.
Saber hesitates for only a second, and she lowers herself to the ground at Irisviel's side and shifts in as close as she dares, which is closer than Irisviel imagined she might: their legs are twined together, and Saber's arm is draped across her waist while Irisviel chooses to rest her hand on the Servant's shoulder; their other hands remain clasped, resting on the scant stretch of concrete between them.
The mana transfer is now palpable, and Irisviel wishes it would make any difference in the end. The power, though, seems to drain away through the hole in her heart.
Idly, at length, Saber muses, "I have never done this before."
Irisviel bites back a giggle as the obvious interpretation flits through her head; she doubts greatly that the Servant is actually referring to their current physical position, so she requests a clarification.
Saber shrugs, a difficult maneuver to execute when she's on her side like this. "Avalon has always been mine to use; I've only ever selfishly sustained myself with its power. In Britain, you see, there was no way to share it like we can here, not without surrendering Excalibur." She tilts her head, and something close to regret shadows her next words. "As a knight, I've always protected people, but I've never…I've never been able to heal them before. It is strange to do so now, but…nice."
"Well," the Einzbern ventures, "in order to hurt someone else, you have to hurt yourself. I guess it would make sense that when you heal someone else, you're also healing yourself."
Saber almost smiles at the notion, and she offers a vague nod.
"But with Avalon, you're practically invincible," Irisviel points out. "You have the ultimate offense and the ultimate defense, not to mention a code of honor you could bend steel around and a remarkable desire to help people. Is there nothing you can't do?" she concludes teasingly.
Saber swallows, licks her lips, stalls for time she knows they don't have. "I don't know how to hold onto you."
She whispers it. There is agony in her throat.
Irisviel's expression softens, and she raises a delicate hand, the motion slow and shaking but executed with the gravest determination. Her fingers light upon Saber's face, just the tips, but then they rest more heavily, as she does not possess the strength to keep the weight away. The skin is warm and alive beneath her touch—and how strange, Irisviel thinks, because neither of them are really alive, are they? Neither of them are even really real—and she follows the smooth curve of her cheek, the sharper angle of her jaw with a curiosity bordering on reverence.
The Servant permits this intimate trespass, her shadowed emerald gaze fixed on Irisviel's, even though the Einzbern is too entranced with watching the play of her ghost-white fingers to return the look. At last, with her own swallow, she answers.
"That's through no fault of yours, my knight," she dismisses sadly, and her thumb sweeps across Saber's chin and just traces the swell of her lower lip. "There is no way to hold onto me now."
Saber stiffens—at the touch or the truth, Irisviel cannot say—and she ducks her head, her gaze falling away; the skin strains around her mouth as she tries to bite the emotions back, and she blinks several times more than she should. "But I want to," she confesses hoarsely, and her eyes flicker back up. "I know it is impossible, but I want to anyway."
Irisviel gazes back at her, and she is amazed by the Servant's beauty, amazed by the little details that no one else has ever bothered noticing—like how her eyes aren't pure green but have sparks of violet and gold, and how her sleek blond hair strays across her face almost artfully, the longest strands catching on lashes, bending across her brow. But mostly she is amazed by the futile tragedy they have come to embody: however close they are, they are nevertheless still too distant.
She can't close this gap—not the chasm of reality that is keeping them apart, but perhaps…perhaps she could cross the few inches of empty air, and perhaps closing that gap will be enough to ease the ache in her soul. Her fingers try to pull Saber in, but while the tips curl, there is no power in them, and she just indents the skin. She grimaces, but gently, because she hardly has the strength for that, either. "Saber," she says, as if the Servant would assume the words weren't addressed to her, or as if she just likes the way it sounds. "Saber, please…kiss me."
The blond regards her for a moment, her face suddenly an indecipherable mask, but with considered grace, she nods. "As you wish, my princess," she breathes, and she remains more than strong enough to shift closer, and the instant before contact is made, Irisviel thinks that maybe Saber is strong enough to change even more than just this moment…
But then their lips are pressing together, and it is gentle and clumsy and chaste, but it still steals all the breath from Irisviel's lungs. Kiritsugu has never kissed her like this, not with such aching, half-restrained love in the curve of his mouth, and she feels tears burn her eyes—stupid, nonsensical tears wrought of too many emotions to count—and they slip down her cheeks in glistening trails until Saber's fingers carefully brush them away.
The Servant offers no words of hollow consolation; she simply kisses her again, and again, and then she draws the other woman's fragile frame into the shelter of her own, tucking her in under her chin and resting her cheek on her hair. She can still feel Irisviel's tears on her neck, hot and damp, and so she threads her fingers soothingly through long snowy strands, and she tightens the muscles in her arms, her shoulders, as if solidifying the embrace in a solitary moment will somehow bestow upon it permanence.
Eventually, the Einzbern slips into dreams, still too weak to maintain consciousness for long, but Saber continues to lay there, patient enough to not be bored by the unchanging hours, peripherally vigilant for flares of enemy Servants. Not once as evening fades into the dark, savage night does it occur to her to loosen her grip, or to stray.
She may not know how to hold onto Irisviel, but neither does she know how to let her go.