Final Fantasy X/Aeons

Valefor


Valefor is the first Aeon that Yuna can summon, which you receive in Besaid, after conquering the Cloister of Trials. She looks like a large eagle, and therefore enemies on the ground have a harder time hitting it than other Aeons, because she can fly. Although Valefor starts out as a useful asset to your party, when you get the other Aeons, she will probably end up weak. Valefor's damage will be able to exceed 9,999 once Yuna activates her Celestial Weapon, Nirvana.

Special Attack
Sonic Wings

Valefor attacks an enemy with a burst of air from its wings. This attack can cause delay in the opponents turn.

Overdrives
Energy Ray, Energy Blast

Valefor is the only Aeon with two Overdrives. Energy Ray is the default Overdrive, in which Valefor shoots a ray of energy under the enemies, blowing up the ground under them. Energy Blast is a more powerful version with a longer recharge time that can be obtained by talking to a little girl with a pet dog in Besaid. Energy Blast is a lot more useful than Energy Ray. She will attack the enemies with a large energy beam through a spinning disc (often killing the subject).

Ifrit
Location Found: Kilika Temple

Unique Attack

 * Meteor Strike:
 * A Non-elemntal attack.
 * It has a longer recovery time than a regular attack.
 * Long-range.
 * Penetrates Protect even though it is a physical attack.

Overdrive

 * Hellfire:
 * "Ifrit encases its foes in a swirling ball of fiery vengeance and detonates it for massive damage to all enemies. All of Ifrit's attacks can exceed 9999 HP damage once you have activated Wakka's legendary weapon, World Champion." - Final Fantasy X Official Strategy Guide.

Ixion
Location Found: Djose Temple

Unique Attack

 * Aerospark:
 * Non-elemental damage
 * Negates magical effects:
 * Protect
 * Shell
 * Reflect
 * Haste
 * Regen
 * Nul Spells:
 * NulBlaze
 * NulShock
 * NulTide
 * NulFrost

Overdrive

 * Thor's Hammer:
 * "Ixion envelops all enemies in a storming vortex, and then disintegrates it. Lightning-based elemental damage is inflicted against all enemies. Ixion can inflict more than 9999 HP damage once you've activated Kimahri's Spirit Lance." -Final Fantasy X Official Strategy Guide

Shiva
Shiva is found in Macalania temple. This ice-based summon spell has a long history across the Final Fantasy franchise.

Shiva's Fayth is a female wearing a cloak over her head. As an ice being, Shiva is auto-equipped with the Ice Eater ability, letting her add ice damage to her HP when damaged. Fire spells do extra damage to her.

Her Aeon attack is Heavenly Strike, and Diamond Dust is her Overdrive.

Heavenly Strike
Shiva drops a large chunk of ice on an opponent's head.

Diamond Dust
Shiva casts an icy plain across all enemies inflicting elemental ice damage(believe it or not). She then snaps her fingers in order to shatter the icy plain to a sea of icy shards, Leaving Diamond Dust an aptly named overdrive.

Bahamut
Bahamut is one of the most powerful Aeons in the game. He is the strongest that you obtain as part of the story, and can do over 9999 damage when you acquire him.

Yojimbo
Yojimbo is a poweful aeon that has godly evasion but lower than average health and defenses.

You have to pay an amount of gil (that you decide) for him to attack. Lower gil results in him commanding his dog to attack, Daigoro. More gil makes him use Kozuka, throwing 3 daggers that will either hit 1 or all enemies. Even more gil will result in Wakizashi, a powerful katana attack that can also hit 1 or all enemies. A lot (and I mean a LOT) of gil results in Zanmato. He draws a katana from the belly of hell, unsheathes its shimmering blade, casts away the scabbard, and lauches a spinning lateral slash at the enemies. A gust of wind will promptly decapitate them. The is a infallible 1-hit-kill attack that works on bosses too, either killing them or sending them into their next form!

It should be noted that all his attack are automatically Penetrating. You cannot teach Yojimbo any abilities. His Overdrive is only increase probability of using Zanmato.

"Yojimbo" is "bodyguard" in Japanese, fitting for a pay-per-kill aeon.

Anima
Anima is Seymour's aeon. You can see it in a scene after the blitzball game in Luca, and you fight it in Macalania. However, you can also get this powerful aeon to fight for you.

Obtaining Anima
The details of how to obtain Anima are found on the Baaj Temple page.

Attacks
Her special attack is "Pain". This attack inflicts damage and Death to the opponent. The first time you see Anima is after the Blitzball game that you get to play at Luca when all the fiends start attacking. That is also the first time you see "Pain".

Her Overdrive is "Oblivion". Oblivion is when Anima takes you into oblivion (hence the name). Inside Oblivion, she breaks the chains that ties her hands down. It delivers hit after hit. This means that you don't need Break Damage Limit to inflict a lot of damage with this Overdrive.

When you first get her, she comes with all elemental Black Magic spells, plus Bio and Death. She also comes with a lot of status inflicting attacks, including Zombie Attack.