Eidolon ( Final Fantasy IV ) Eidolons , known previous to the Nintendo DS remake as summoned monsters or Phantom Beasts , are the summons of " Final Fantasy IV " , " Final Fantasy IV - Interlude - " , and " " . Eidolons are clearly differentiated from other monsters ; they are intelligent , can speak the human language , and refer to the monsters Cecil and his companions fight as their cousins . They build shop s , manufacture and sell items to the rare traveler that finds their world , write books , and so forth . Eidolons can be summoned by Rydia using the Summon ability . Profile . Because of their isolation , Eidolons are naturally wary of humans who are not Summoners . The bond between an Eidolon and their Summoner is unique . The Summoner must first defeat an Eidolon in battle , then they can use them as a summon . If the Summoner ' s Eidolon is killed , the Summoner dies as well . The Eidolons live in the Feymarch , a plane usually inaccessible to humans , although a portal to this world exists in the Underworld and Leviathan is able to travel to and from the surface world by undisclosed means . In Feymarch time flows faster than normal , and a few weeks or months in the human world can be years in the Feymarch . According to the books in the library in this world , Leviathan and his queen , Asura , are the rulers of the world , but Bahamut is their God and the ruler of all monsters . Bahamut lives on the Red Moon . Young Eidolons are called Whytkins , and take the form of Rydia ' s Eidolon Whyt . In this form , they can grow to take on the forms seen in the other Eidolons . Whyt and his parents stay Whytkins so that new Eidolon children can be born . Though Whytkin have no abilities of their own , they have hidden potential that allows their power to be greatly increased . Not all Eidolons grow up from Whytkin , however - at least one , Odin , is born from a deceased Dark Knight instead through undisclosed means . Eidolons in " Final Fantasy IV " seem to take on humanoid forms . Leviathan introduces himself as merely " some old man " until the party defeats Asura . In the Lair of the Father , Bahamut appears as a robed man wearing a head ornament . His two guards also take the form of children . Story . " Final Fantasy IV " . The Kingdom of Baron , fearing the power of the Eidolons , sends Cecil Harvey and Kain Highwind to the village of Mist to deliver a package , a Carnelian Signet . The Mist Cave connecting Baron and Mist is guarded by one of the summoners , who has conjured a Mist Dragon . Cecil and Kain slay the dragon to pass , unaware that this act also kills the summoner . At Mist , the Carnelian Signet releases bomb monsters that burn the village down . Cecil and Kain attempt to take Rydia , the daughter of the summoner they killed , to safety , but in her rage for them she summons the Eidolon Titan , who causes an earthquake separating the trio . Many the women and children of Mist aside from Rydia are killed in the incident , along with many of the village ' s prominent summoners . While Rydia is the only prominent summoner to appear in the series , the bloodline of summoners remains in the villagers , though weak . Some time later , as Cecil and his allies including Rydia set sail to Baron from Fabul , Leviathan attacks the ship to claim Rydia , swallowing her and taking her to the Feymarch to protect her and to teach her to hone her skills as a Summoner . Due to the time shift between dimensions , Rydia grows from a child into a young woman in the Feymarch , eventually returning to aid Cecil and his allies with her increased powers . In the ending , Rydia chooses to live with the Eidolons in the Feymarch . The player has the option after Rydia rejoins the party to recruit additional Eidolons for her to summon . At the Feymarch the party can challenge Asura and Leviathan to have them grant Rydia their power . After this , Bahamut on the Red Moon and Odin in Baron Castle can be challenged . Assorted monsters may drop items that teach Rydia how to summon them as Eidolons . " Final Fantasy IV - Interlude - " . Rydia leaves the Feymarch and the Eidolons to visit Damcyan . In the underground , Cecil and his allies explore the Sealed Cave and apparently find Rydia in the Crystal Chamber , who tells them she is being called by the Tower of Babil . At the Tower the party defeats a quartet of elemental monsters which grant her the power to summon Ifrit , Shiva , Titan and Ramuh , before she abandons the party . At the top of the tower the party discovers Rydia is an impostor , and she summons the four Eidolons against them . With the four dispatched the Rydia impostor summons Bahamut , but the real Rydia arrives and returns Bahamut to his senses , causing him to vanish and allowing the party to defeat the impostor . A flashback at the start of Rydia ' s Tale reveals that she now lives in Mist , Asura rejecting her from the Feymarch due to her belief Rydia belongs in the human world , though many of the other Eidolons miss her . Prior to the start of the game , several Maenads visit the Feymarch and petrify the Eidolons , preventing Rydia from summoning them and corrupting their minds so they serve the Maenads . Other Maenads visit the Red Moon and inflict the same ailment on Bahamut . The Maenads use the Eidolons to terrorize the world in their campaign for the Crystals . Titan attacks Agart , Ifrit attacks Eblan , Shiva attacks Troia , and Ramuh attacks Mysidia . Asura and Leviathan are used by the Maenads on the Red Moon , while Bahamut and Odin are put under the control of the Maenads at Baron Castle . The only Eidolon to not be affected , aside from the Eidolons obtained as monster drops , is the Mist Dragon , who is protected by the combined energy of Mist ' s villagers and the spirit of Rydia ' s mother , who summon the Dragon to protect the village . During the final chapter " The Crystals " , the party travels the world freeing the kingdoms from the Eidolons , depending on the player ' s actions either killing them or allowing Rydia to bring them to their senses and rejoin her . At Baron , a Maenad summons Odin against Cecil ' s other allies , but Odin recognizes them as citizens of Baron and refuses to harm them , turning on Cecil and knocking him from the Maenad ' s control . Rydia and the other party members arrive , reclaiming Odin and defeating the Maenad . On the True Moon , Asura and Leviathan are deployed to guard an energy barrier preventing passage further into the dungeon . Depending on the player ' s actions , they are either killed or Rydia awakens them . Later , a Maenad summons Bahamut against the party . If Asura and Leviathan are freed , they assist Rydia in bringing Bahamut to his senses , otherwise , he must be killed . In the ending , Asura and Leviathan visit Rydia at Mist , they and the other Eidolons restored to their normal selves . List of Eidolons . With the exception of Whyt from the " Final Fantasy IV " DS version , all of the Eidolons and their attacks from " Final Fantasy IV " are the same in " Final Fantasy - Interlude - " and " Final Fantasy IV : The After Years " . They also happen to appear in every sequel . Other appearances . " Pictlogica Final Fantasy " . Some of the Eidolons appear in " Pictlogica Final Fantasy " . " Final Fantasy Airborne Brigade " . Some of the Eidolons from " Final Fantasy IV " appear in " Final Fantasy Airborne Brigade " . " Final Fantasy Record Keeper " . Leviathan from " Final Fantasy IV " appears as a boss in " Final Fantasy Record Keeper " . " Final Fantasy Trading Card Game " . Some Eidolons have cards in the Japanese " Final Fantasy " trading card game . Etymology . In the English localization of the DS version , " Eidolon " is ( aye - " doh " - lon ) . The summons in " Final Fantasy IV " did not have a specific name until the DS version of " Final Fantasy IV " was released . The game ' s translator , Tom Slattery , was the one to choose the term " Eidolon " :