Just like in the other FF games, in FFX you can also summon monsters a.k.a. Aeons (Eidolons in FFIX, GFs in FFVIII and Summons in FFVII) But, this time, they don't only stay out for one turn. They are just like any characters. The Aeons even have overdrives.

Acquiring Aeons
In FFX, there is a different way to get Aeons unlike any other previous FF title. You have to travel to different temples at various villages. Once you arrived at these temples, you have to pass the Cloister of Trials (if you need help, go to the Temple Guide page). As you have done that, the summoner in your party, Yuna, prays to the Fayth. The summoner now gets the Aeon.

Aeon Abilities
In FFX, all the Aeons except Yojimbo and The Magus Sisters can learn abilities if you obtained the item "Summoner's Soul". They could learn abilities, white magic, black magic, and other special moves. To teach an aeon an ability, you must have the required amount of an item that teaches the special command.

Aeon Attributes
When Yuna beats Belgemine, you will recieve the item "Aeon's Soul'". Now, with this item, you could raise your aeon's stats. You will be able to increase its Strength, Defense, Agility, Luck, Evasion, Accuracy, Magic, Magic Defense, HP and Mp. You will need a cerain kind and amount of sphere to do this. Think, now you make the most powerful aeon.

Aeons
There are 8 aeons in all in FFX.

Name:Valefor
Specials:Sonic Wing
Black Magic:Fire -4MP
Blizzard -4MP
Thunder -4MP
Water -4MP
Overdrive:Energy Ray
Energy Blast

Name:Ifrit
Specials:Meteor Strike
Black Magic:Fire -4MP
White Magic:Null-Frost -2MP
Null-Blaze -2MP
Overdrive:Hell Fire

Name:Ixion
Specials:Aero Spark
Black Magic:Thunder -4MP
Thundara- 8MP
Overdrive:Thor's Hammer

Name:Shiva
Specials:Heavenly Strike
Black Magic:Blizzard -4MP
Blizzara -8MP
White Magic:Null-Frost -2MP
Null-Blaze -2MP
Overdrive:Diamond Dust

Name:Bamahut
Specials:Impulse
Black Magic:Fire -4MP
Blizzard -4MP
Water -4MP
Thunder -4MP
Fira -8MP
Blizzara -8MP
Watera -8MP
Thundara -8MP
Firaga -16MP
Blizzaraga -16MP
Wateraga -16MP
Thundaga -16MP
Overdrive:Mega Flare

Name:Yojimbo
Specials:Digoro
Kozuka
Zanmato
Wakizashi
Overdrive:N/A

Name:Anima
Special:Pain
Overdrive:Oblivion

Name:Magus Sisters
Specials:Camisade
Razzia
Passado
Overdrive:Delta Attack