From the minute her vydran had told her that Yuna had chosen to take the summoner's journey, the wheels in her head had been turning. How can I save her? How do we stop this? And she'd tried so hard, through kidnappings and old creepy unsent monks and Sin. Eventually she had Tidus on her side, too, and for a while it had boosted her hope and made her believe that their summoner, their Yunie, would come out of this unscathed and--
and now, she is not a guardian. She is a fifteen year old girl holding her dying cousin in the smoking remains of Spira's hope.
Rikku finds herself irrationally angry that Tidus is not the one in her place, comforting Yunie and being reminded with every rattling gasp that nobody is infallible - but she knows he comes from a world where death is an occasion and not a way of life, and he is not suited for it.
Yunie is silent, withdrawn - her face is pale and sweaty and pained, her entire body trembling with the effort of simply being, but she still manages a small smile at her cousin, and asks - so quietly Rikku isn't sure she hadn't simply hearing things - for a song.
The smile she offers in return is fragile but genuine; the Al Bhed girl channels every good memory she's had with Yunie into it - meeting, laughing, holding her hand tight to remind herself that she has family. And because she could never deny her Yunie anything, she agrees.
So she bites down hard on the inside of her cheek, hard enough to pierce the skin and make her bleed - there's no way she can cry now, not now, not when Yunie knew all along that this was how things would be - and she runs her shaking fingers down the sides of Yuna's face.
She breathes deep through her nose, once, twice, and begins.
It hadn't really been a conscious thought - the tune in her mind had been an old lullaby, the soft kind that had no words - and yet she sings a broken version of the Hymn of the Fayth, the pieces that had been clumsily translated into common tongue and then again into Al Bhed; her voice catches more than once and she stumbles where she has forgotten the words. If Yuna notices, Rikku sees no indication.
She sings until long after her cousin's eyes fall closed, until the last breath catches in Yuna's lungs and sticks; until her throat is raw and Wakka is forced to pry her away so that they can cover Yuna's body - her body, she repeats to herself, because it's not really Yuna anymore - and get her ready to make her final journey back home.
Rikku leaves that place before the rest, locking herself away in the small cabins of the airship; she reemerges only hours later, her eyes red and her skin blotchy, but determination written in every line of her face. She won't let her cousin's sacrifice mean nothing.
And four years later, the Al Bhed finally have their own statue of their High Summoner - a shining beacon for the center of their new Home, carefully crafted by deft hands out of their best polished metal.
Rikku is not there to see it, because she's long gone to spearhead the next battle against Sin, preparing before it ever happens; she teaches those who wish to put away the practice of sacrificing summoners forever to fight, to break free of Yevon's teachings and develop machina. She will fight Sin, she knows, until the day Spira can truly be free - even if it kills her.