Da Proof
1.) Sorceresses may not age. I mean, think about it. Cid could've been Edea's age when Edea recieved her powers. Then he aged and she didn't. That would be why Edea looks so much younger than Cid. Also, it never talks about a sorceress dying, though it does talk of Adel from 'the far past'. If this is true, Rinoa could live on and become Ultimecia.

2.) Why would Rinoa try to kill Squall? Maybe- just maybe- since she wouldn't age, and Squall would, she would be unable to take the pain. Listen to what she says after you beat her:
"Reflect on your...
Childhood...
Your sensation...
Your words...
Your emotions...
Time...
It will not wait...
No matter...
...how hard you hold on
It escapes you..."
This totally supports what I just said earlier!

3.) Remember at the field near the orphanage, when Rinoa said something along the lines of "If I can't control myself...you can kill me , Squall. But only you...I guess it's okay if it's you..." Well, she became Ultimecia and could no longer control her powers. So she goes back into time to let Squall kill her...just like she promised.

4.) Ultimecia has her castle RIGHT next to the field where the promise from the intro was made. Why there? Could be for design purposes. Or, it could be because she is waiting for Squall.

5.) Remember how Rinoa borrows Squall's ring? Well, she never gives back the origional. We know this when she says she put on HIS ring in her dream which she described at the field. Now, if you can get Doomtrain from Soloman's Ring, why couldn't you get Griever from Squall's Ring? Plus...how else would Ultimecia have the Griever GF?

6.) A lot of emphasis is put on Rinoa's angel motif. Like, for example, the wings on her parka and her limit break. Rinoa's wings are white and Ultimecia's are black. White symbolizes good, and black symbolizes evil. It could be a natural progression. There's evidence of this in scenes from the ending. It appears Rinoa's wings are changing during one of the FMVs. It appears her wings are changing colors.

7.) There are only 3 FMV shots of Ultimecia in the game, all very fast at the end. Plus, all of the shots are mixed in so that they all cut into FMVs of Rinoa. One appears right before Rinoa's wings appear to change color. Just after this Squall falls and yells out. Maybe Squall has seen the prophecy of Rinoa turning into Ultimecia? He CAN see the future after all...it is time compression...

8.) If you compare the pictures, Ultimecia and Rinoa have VERY similiar eyes, mouths, noses, face shapes, and hair parting points. Did you notice?

Well?
Are you convinced? Creepy, isn't it? My personal belief is that Square put in JUST enough evidence to make you think about it...they don't want you to be sure exactly what happens. Just believe what you want to...d'oh, that sounded really corny, didn't it? lol...Oh, by the way; here's the link to The SeeD Who Loved Me, the site where I got a lot of this info from! ^_^

The SeeD Who Loved Me