Aeon InformationDuring the course of Final Fantasy X, Yuna has the ability to gain control of up to eight aeons, three of which cannot be find without going off the beaten track... If you select Yuna's Summon command, all known aeons will first be listed. Once you've selected an aeon, the creature will fight the battle for you alone. It will be able to do a number of attacks and spells, of which more are learnable. If you select Dismiss, you will recall the aeon and send your characters back into battle. An aeon will vanish onces its HP reaches 0, your characters will automatically return to battle after this happens. To recover your aeons, you have a few options. Firstly you can use a Save Sphere to heal your party (and aeons.)
Secondly you can rest at an Inn. Thirdly you can fight a certain amount of battles, and your aeon will automatically be revived. The table showing the number of battles is below:
Developing AeonsYou also have the ability to develop the attributes on your aeons. You'll have to be in possession of the Summoner's Soul if you want to teach aeons abilities and you have to have the Aeon's Soul to raise their attributes.
Summoner's Soul can be obtained after fighting Belgemine in Moonflow or in Remiem Temple
Aeon's Soul can be obtained after fighting Belgemine in the Calm Lands or in Remiem Temple.
Go to the Aeons menu and press Circle to access the Abilities and Attributes. Once you've selected an ability or attrubite, the options avaliable will be highlighted in white on the left-hand side of your screen. You'll see the items required to the right. The figure in the left-hand circle indicates the quanitiy of avaliable items, while the figure in the right-hand circle indicates the number which will remain afterwards. Once you've confirmed your decision, your eon will have learned a new ability or increased an attribute.
Although you can theoretically improve attributes using the same method as that detailed above with regard to abilities, there are two other methods of upgrading an aeon's attributes. With exception of Luck, all levels are automatically increased by entering battle. In this regard it makes no difference who participated, fled or was knocked out. The first increase takes place after the 60th battle (from the time the aeon was first avaliable). From then on, the levls can incrase up to 18 times at 30 battle intervals.
The aeon's levels will also increase in tanderm with Yuna's levels. All aeons' Luck levels will increase equally, while the other levels will increase automatically with Yuna's and may even exceed them depending on the aeon in question. However, if this happens, the other levels will increase less significantly.