Sin, Dream Zanarkand theory

[Kyrel]

Even though that came from the ultimania i don't think that's 100% right because in the very end of the game when you fight the 7 aeons then yu yevon, the reason you have to fight the aeons is because once you kill braskas final aeon yu yevon detaches from it and begins attaching to each aeon yuna summons. Plus if the the reason the summoner dies is because he/she kills the final aeon and then dies because of the mental connection breaking abruptly how is it that the party is the ones to kill braskas final aeon. Like i said yu yevon possesses the final aeon kills the summoner and becomes the next sin.

You're right, my bad. I misquoted it, the mental bond is broken when Yu Yevon invades the Final Aeon. That's why the summoner dies.

[the_savior21]

That's much more understandable