Aeon (Final Fantasy X)

Aeons are the summons in Final Fantasy X and Final Fantasy X-2 (however they cannot be summoned in FFX-2). The Aeons are obtained by completing the Cloister of Trials at each of Spira's different Temples. They are different from most summons in the Final Fantasy series as they can be controlled by the player once summoned and they can only be summoned by Yuna.

List of Aeons
Only five of the game's Aeons are required as dictated by the story's plotline. The other three are optional, and must be searched for.

Required Aeons
(In order of appearance)
 * Valefor (Obtained in Besaid)
 * Ifrit (Obtained in Kilika)
 * Ixion (Obtained in Djose)
 * Shiva (Obtained in Macalania)
 * Bahamut (Obtained in Bevelle)

Optional Aeons

 * Yojimbo
 * Anima
 * The Magus Sisters

Using an Aeon
Final Fantasy X features the ability to have direct control over summoned creatures, in the same way a player would control a character. Once Yuna summons the desired Aeon, all other characters vacate the battle field, and offer control of the Aeon to the player (with the exceptions of Yojimbo and The Magus Sisters (see respective articles for details)).

Overdrives
Aeons, like the player characters, have Overdrives of their own (Again, with the exceptions of Yojimbo and The Magus Sisters). Their overdrive meters can be charged by giving and taking damage in battle. The Boost ability will increase the rate at which Overdrives are charged, but the Aeon will suffer more damage per attack. The Shield ability will reduce both the amount of damage received, and the rate at which the gauge is charged.