Attack: Judgement Bolt
MP Cost: 20
Gem: Peridot
Acquired from: Once you enter Pinnacle Rocks, you will be asked to complete a quest for him. Answer his questions in this order: Beginning, Cooperation, Silence, Hero or Human.
Shiva
Attack: Diamond dust
MP Cost: 20
Gem: Opal
Acquired from: When you first enter Disc 3, you will get back Eidolons from Dr. Tot.
Ifrit
Attack: Flames of Hell
MP Cost: 20
Gem: Topaz
Acquired from: When you first enter Disc 3, you will get back Eidolons from Dr. Tot.
Atmos
Attack: G-Force 199
MP Cost: 25
Gem: Amethyst
Acquired from: When you first enter Disc 3, you will get back Eidolons from Dr. Tot.
Odin
Attack: Zantetsuken
MP Cost: 30
Gem: Dark Matter
Acquired from: Auctioned off at Treno Auction house or stolen from Super Boss Ozma.
Leviathan
Attack: Tsunami
MP Cost: 40
Gem: Aquamarine
Acquired from: Taken from the Iifa Tree during war against Queen Brahne (you will automaitcly get it)
Bahamut
Attack: Mega Flare
MP Cost: 80
Gem: Garnet
Acquired from: Given by Beatrix in disc 3.
Ark
Attack: Eternal Darkness
MP Cost: 100
Gem: Pumice
Acquired from: You must have 2 pumice pieces first. Locate Hades in Memoria, he is in a area that seems like it is underwater. Go all the way to the end, and make a hardright, Zidane will dissapear and then just press x to talk to hades. You can Synth 2 pumice pieces into a Pumice, which in turns gives you Ark.
Eiko can use these Eidolons:
Fenrir
Attack: Terestrial Rage or Millennial Decay
MP Cost: 30
Gem: Sapphire or Maiden Prayer (Depends upon which addon is equiped for what version appears)
Acquired from: Comes with Eiko.
Carbuncle
Attack: Ruby, Emerald, Pearl, Diamond Light
MP Cost: 24
Gem: Ruby, Emerald, Moonstone, Diamond (Depends upon which addon is equiped for what version appears)
Acquired from: Comes with Eiko.
Phoenix
Attack: Rebirth Flame
MP Cost: 32
Gem: N/A (use Phoenix Pinion to summon)
Acquired from: Many different places.
Madeen
Attack: Terra Homing
MP Cost: 54
Gem: Ribbon
Acquired from: Learned from Mog when he attempts to save Eiko from Zorn and Thorn.