Afew questions...( Spoilers)

Im playing the game at the moment,and Im a tad bit confused.Maybe you could help me understand abit better without spoiling the ending for me?Or not too much.

At the farplane,Auron and Rikku were the only two who didnt go into it.Rikku because she was an albehd,but i cant remember aurons reson.When Jyscal came from the farplane,Auron fell.I was thinking,because he was Braskas guardian aswell as a warrior monk,perhaps he was like symore and didnt accept death or didnt get sent.I wasnt sure.Could somone maybe explain this abit?If it will spoil the ending,just say so and I will wait.

Aslo,i found a 'Jecht Spher' in the woods,after the escape from bevell.Is there more then just this one and can i see it again once i have it?

As far as your first question is concerned, yes, Auron is an unsent; that's all I'll say without spoiling anymore.

As far as your second one goes, no, you cannot view it again. However, there are more than one you must find if you wish to unlock all of Auron's overdrives.

Yes there are many sphears scattared around spira, and not only does it give Auron his overdrives but it also is a great story line. The more you find the more, well at least I understood the story. It makes the story better I think.

Yeah, he's an unsent ... he's dead ... anyways you have to find all the sphere to get the overdrives for both Tidus and Auron I think... If I remember correctly >.<

There are 10 spheres in total which you need all of them to unlock Aurons forth overdrive attack.

They don't have any effect on Tidus' overdrives, you gain them by just using them each a certain number of times.

alright,cool!Thank you all very much!