[Tidus returns to the "Ruins" from the start of the game, and jumps into the water. Tidus, Wakka, and Rikku are shown floating in it]
[Geosagaeno fight]
[[...] after that, you go into the Chamber of the Fayth. Yuna prays. The ghostly image of the fayth appears: it's Seymour's mother!]
Yuna
"You are Maester Seymour's mother."
"So you know. Yet still you seek my aid?"
"My son... Do you not hate him?"
[They're silent]
"It is all right."
"He is the one who sowed the seeds of hatred. He is to blame."
[She turns. We see an image of the young Seymour, sitting, crying]
"But I am at fault for letting him become what he was."
[Scene change. We see a slightly older Seymour just....standing in a room with several bouquets of flowers]
"He was always alone--half Guado, half man."
"I wanted to give him the strength to live by himself."
"And so I became a fayth."
"But..."
"because I let him taste power, he began to thirst for more."
"He was not satisifed with my aeon. He wanted more. More power."
[Scene change back to the group]
Tidus
"And he found Sin."
"Yes."
"Come, summoner. I will bestow you with my power:"
"The Dark Aeon, Anima."
"Destroy Sin, and my son's obsession with it."
"Though it is small recompense for what I did to him."
Baaj Temple Transcription