If Ulti=Schala and TD=Griever then it explain a lot of what happens in the end.
Ulti has been junctioned to Griever all the time.It was the intention of her possessor to give Griever to her.That way she would forget about
everything.
She just draw Griever from Squall like when we draw GF from people.
Her possessor wannas to junction her to griever to prevent her from telling Squall and Company things about the past.
When she is about to die she starts to remember things and say the last lines to our friends.
These lines are about remembering ones childhood and things like that.
They arenīt menacing suggesting she was not possessed anymore.
But our characters keep attacking her without knowing it.