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Final Fantasy X Aeons

Valefor

Special Attack: Sonic Wings

Overdrive: Energy Ray/Energy Blast

Valefor is Yuna's first and favorite Aeon. Valefor can fly which makes help immune to ground attacks and is also unique in the way that he can learn two Overdrives. His first Overdrive is Energy Ray and his second, more powerful Overdrive is Energy Blast which can be learnt from an item found in Besaid. Valefor's Overdrive damage can exceed 9,999 damage when you have Yuna's legendary weapon, Nirvana.

Ifrit

Special Attack: Meteor Strike

Overdrive: Hellfire

Ifrit is Yuna's 2nd aeon found at the Kilika Temple. He is a fire element which makes him weak against ice and he can heal himself with Fire. His Hellfire Overdrive can exceed 9,999 damage when you have Wakka's legendary weapon, World Champion.

Ixion

Special Attack: Aerospark

Overdrive: Thor's Hammer

Ixion is Yuna's 3rd aeon found at the Djose Temple. Since he is a Thunder element, he can heal himself with Thunder attacks. His Thor's Hammer Overdrive can exceed 9,999 damage when you have Kimahri's legendary weapon, the Spirit Lance.

Shiva

Special Attack: Heavenly Strike

Overdrive: Diamond Dust

You receive Shiva at the Macalania Temple as Yuna's 4th summon. She is an Ice element so she can heal herself with Ice attacks. Her Diamond Dust Overdrive can exceed 9,999 damage when you have Lulu's Onion Knight.

Bahamut

Special Attack: Impulse

Overdrive: Mega Flare

Bahamut is found at St. Bevelle Temple. He is pretty strong physically. His attacks do more damage then other aeons and his ability to use magic like Firaga, Waterga, Thundaga and Blizzaga make him a powerful magic user. His Mega Flare Overdrive needs no legendary weapon to do over 9,999 damage as he can exceed this limit by himself.

Yojimbo

Yojimbo can be found in the Cavern of the Stolen Fayth. You must pay Gil to have him attack. Daigoro and Kozuka attack one enemy. Wakizashi attacks one enemy or all and Zanmato will attack all enemies. If you have Auron's Masamune, Yojimbo can do over 9,999 damage.

Anima

Special Attack: Pain

Overdrive: Oblivion

Anima was formerly Seymour's Aeon. He is a VERY strong Aeon. His Pain attack will likely kill an enemy in one hit but Anima will have quite a long delay time after use. His Oblivion overdrive needs no legendary weapon since it already does over 9,999 damage. It is one of the most powerful Overdrives in the game.

Magus Sisters

Cindy, Mindy and Sandy form the Magus Sisters. They are a unique Aeon like Yojimbo. You must talk to them if you want them to attack and they attack on there own. If all three of the sisters' Overdrive gauges are full, the Combine Powers option appears which allows the Magus Sisters to join there attacks together to do over 9,999 damage. They need no legendary weapon to do over 9,999 damage.