Chapter 1: endless mountain of cedar trees, i walk alone, i walk alone
Frost gathers in her white-streaked hair as she climbs Gagazet. The pillars loom, and she hears again the echo of the Hymn, dark ghost-voices of the lost Ronso.
With each step, she grows closer to faltering, her old limbs failing in the relentless cold. With each step, she grows closer to remembering. She forces her hands to flex around the grip of his mightiest sword, and thinks of the way he would arch that single sarcastic eyebrow at her if he were here.
This is the trial of Gagazet, the frost lined halls in which so many have fallen. Their bones litter the crevasses, their weapons are many-colored tears glittering across the velvet white skin of the eternal god, the eternal goddess, the mountain that will not bend.
She shoves the sword into the ice to take one last step. Leaning against it, standing at the roof of the world, she coughs, long and hard. Blood stains the snow, disregarded. She shakes back her hair, the beaded plait as long as her grief, strong as her love, and says in Al Bhed, "Now who's the badass, Auron?"
She presses the detonator. And as the mountain comes to Rikku -- she laughs.
Chapter 2: Very Optional Notes
This is mainly explanation for anyone unfamiliar with the game.
Rikku is Al Bhed, and they're a group of mechanically inclined gypsylike folk who are persecuted by the Yevonites -- the mainstream, governing religious group -- but often get back at them in other ways ("raised up by merchants and drugstore liars"); also, her overdrive is 'mix,' with which one can handily blow things up, thus how I figured she'd want to go out if it came down to it. She's very old here, and terminally ill, and dying by inches isn't her style.
The song plays off the old story about Muhammad summoning a mountain to him, and the mountain not coming because, he explained, God was merciful and had intervened -- the mountain would have crushed all the people beneath it, if it had obeyed. This doesn't happen in the song, so perhaps the narrator is insane... in this case, since the 'god' would be Yevon, who was not known for mercy, the mountain definitely crushed everyone that it could across its existence.
I know that there was Stuff discovered there in X-2, but I'm ignoring X-2 except the bits that back up my OTP. *whistles, looking around*
The central premise, which is a spoiler (and I tried to stick all the spoilers below)...
...is that Auron died at the base of this mountain, after crawling back down it, ten years before the game starts. His original Summoner and fellow Guardian gave their lives in hope of saving the world, after which Auron, who had been a warrior monk from the world's main temple, found out that the whole system was a big lie and the cycle of destruction would go on ("forked-tongue story"), went a little nuts and attacked someone way too powerful, got struck down and went on with nothing but sheer determination to tell the truth anyway. Opinions vary as to where exactly Auron died based on vagueness/contradiction in-game, but regardless, if he hadn't had to fight his way back across Mount Gagazet alone (where many past Summoners with multiple Guardians fell) with already near-mortal wounds, he probably would've survived.
Rikku was 15 in the game to Auron's 25 + 10 years 'unsent,' and they hardly interact in canon, so it's quite one-sided if anything. But in the sequel, she has his sword Masamune (and both she and Yuna are growing out braided locks of hair that are fanonically connected with mourning). So, if nothing else, he certainly had a large impact on her and the future of Spira.