Within the world of Final Fantasy X, the concept of the Summoner class and magic is transformed into something more mystical, and, even religious. The role of the Summoners and the ‘summons’ [which are called Aeons in this series] hold the fate of the world, at least for a little while, in their hands. It is a sacred, holy path that only few follow, and none survive on.

When a person decides to be a summoner, they go through years of training before they actually use their abilities, and during that time they are called ‘apprentice summoners’. After they have completed their training, they head out to a Temple, which holds the Aeon as well as a labyrinth of tests, the Cloister of Trials, which they must complete before the Chamber of Fayth where the Aeons body and spirit resides. The only people who may accompany a summoner through the trials are Guardians, people who swear their lives to protect a summoner who is on their pilgrimage to defeat Sin. However, no one but a summoner may enter the Chamber of the Fayth.

Throughout Spira there are numerous temples [even hidden ones] that hold Fayth that the Summoner may pray to. A summoner must receive all of the Aeons before they can go on to defeat Sin, hence the pilgrimage around the world.

While the concept of the Aeon seems rather simplistic and similar to that of any other series, it becomes a bit more of a shock as the story progresses. Each Aeon is the powerful monster-esque representation of the Fayth… and the Fayth themselves are souls of people who sacrificed their lives to help with the fight against Sin, embalmed in a sphere and their souls trapped in a suspended state, left to dream for eternity.

Many of these people have the choice to join in to help the fight against Sin. They are average people, as you can see before going to your final battle with sin if you visit each temple in game. But, as their dreams became incorporated with the dreams of the dead from centuries past, they realized all the truths of this world and what it meant to be an Aeon. An eternity of dreaming became tiresome, and they helped move forward the revolt against Yu Yevon so they could rest on the Farplane in peace.

1000 years ago, the world now called ‘Spira’ was engaged in war. Two great cities: Bevelle and Zanarkand were engaged in war, and Bevelle with their great machines and technology, would surely defeat Zanarkand and their summoners. Yevon, the leader of Zanarkand at the time, refused to let this be, and decided to create a dream world where his city would exist forever by the dreams of all the people. So, they were all embalmed and created this ‘Dream Zanarkand’. Buy, the great summoner Yevon in his heightened hatred for Bevelle and their destructive machines also created Sin; a powerful and large beast that would destroy anything he saw.

Yunalesca, daughter to Yevon, decided that the only way that they could destroy this destructive beast is by creating a summon powerful enough to counteract it. With that, she being a powerful summoner herself, turned her one true love Lord Zaon into the Final Summon, an Aeon whose power could destroy Sin’s armor because of the emotional bond between the Fayth and the Summoner. Because Yevon’s inhumanity merged with Sin, he would come forth after the armor’s destruction, fuse with the Final Aeon to become Sin once more, and, as a result, kill the summoner.

After that, a temporary calm would come as the Final Aeon slowly transforms into the machine-hating Sin we all know.

Making note of the above concerning the endless cycle of death, the only way that it can be stopped is by getting rid of what makes Sin come back, not Sin itself. The group of main characters realized this when they were determined not to let Yuna be killed also. Knowing the personality of the last Final Summoning [Jecht] they devised a plan to enter Sin and destroy Yu Yevon from there and end this world’s destructive path.

Each Aeon [that Yuna possed at the time] was destroyed so that their Fayth could rest, so that one could not before Sin. Then Yevon was destroyed from within, in turn destroying the Final Summoning he merged with [Jecht]. The dreams of Zanarkand of the rested souls in Spira stopped their dreams and rested at the Farplane.

Of course even though the major threat in Spira was destroyed and many of the souls that were once locked in an eternal dream prison were lay to rest, there were still a few souls unable to subside their dreaming. In the aftermath and the reconstruction, all of the secrets of Yevon, as well as the war-torn tales of the past rose and lived on to create only more havoc for our heroes [or should I say heroines?].

Because of the nature of the Farplane, many of the Aeons that were once put to rest were jarred by the hatred of the past [sort of a lame concept, no?] and returned to this world as an obstacle in the story of Final Fantsy X-2. In any case, of course they and the other spirits that dwelled in Spira were sent and put to rest.