When I said "disprove my theory with information", it can be either evidence based or not.
Rinoa: Hmm...so this L I O N of yours, does it have a name?
Squall: Of course. Griever.
Rinoa: So that's what you call it. You know Zell said he'll make me one
exactly like it. Who knows, maybe I can become like a lion, too. That'd
be crazy, huh!? I mean, everyone might, y'know, get the wrong idea
about us.
It implies that she actually likes the norm of Griever. At that time, she wasn't possessed, either. I don't recall any event that Squall has told Rinoa about Griever or implied things about Griever (strength and pride)
WHILE she was possessed.
So, how did Ulti knew about Griever? She CAN'T manfiest Griever out of Squall WITHOUT knowing the existence of Griever in the first place, see what I mean? Rinoa IS the only person who knew about Griever, Squall even told her the name.
I don't think Ulti has the ability to read Squall's mind, so how? That's why my theory seem to make sense, Rinoa is Ultimecia and created Griever due to her insanity. I'm not saying it's TRUE but it seems very plausible to me.
In the game, when Rinoa was possessed, she went absolutely mad in the space station = insanity.
So if Rinoa is Ulimecia, she will become insane and creates Griever because she acknowledged Griever from Squall in the first place. Insanity = leads to unpredictable things.
There are a lot of evidences that Squall has careless attitudes against his friends, including Rinoa. Yet, as the story goes on, Rinoa always became on Squall's side, caring about him, loving him, etc. Does that sound odd? With my theory, it doesn't seem odd to me anymore.
She saw it, good faith has returned, after that event, Squall has found her. That's because of Griever, when she looked at Griever, she thinks of strength and pride, so she got good hope.
-------
Adel grabbed Rinoa.
Rinoa passed out.
When she woke up, this dialogue imploded:
Rinoa: I...was inside Adel... The young Adel...
and then Laguna said Ulti was inside Adel. That seems Suspicious.
You know, the whole event when Adel woke up. The monsters started fleeing from the moon. Yes, the moon where it symbolizes Griever. Seems Suspicious as well.
I wonder who is that? A new witch in the future? She has similar wings as Ulti, Edea and Adel. Shiva is naked, that woman in the picture also seems to be naked, hmm.