Mysterious Girl ( boss ) The Mysterious Girl is a recurring boss in " " . She frequently fights alongside an Eidolon . Many of the battles against her are unwinnable . Battle . Palom ' s Tale . The battle for the most part is scripted . Palom and Leonora should use Particle Bomb until the Mysterious Girl calls Shiva to defeat them . Edge ' s Tale . As in Palom ' s Tale , the Mysterious Girl cannot be defeated . The party should attack until she summons Ifrit , and the party will flee from her . Porom ' s Tale . Porom will be assisted by the Elder of Mysidia . He has access to all White Magic but Holy . Like Palom ' s fight , this is mostly scripted . Porom should equip a bow and the Elder cast Haste and Berserk on her to increase her damage output and speed up the fight , which ends with the Mysterious Girl summoning Ramuh to defeat them . Lunarian ' s Tale - Impact Crater . Golbez and Fusoya will fight the Mysterious Girl , who has summoned Asura at the start of the battle . Asura cannot be defeated and their attacks must be focused on the Mysterious Girl . She will attack them with strong magic and Binding Glare , which inflicts Paralyze . Fusoya should cast Haste on himself and Golbez and Slow on the Mysterious Girl , and place them both in the back row to reduce damage from Asura ' s physical blows . Asura ' s presence means the Mysterious Girl is treated as being in the back row , reducing damage from physical attacks , so magic is most effective . Use level three magic of any element from both Fusoya and Golbez , healing when needed . Lunarian ' s Tale - Crystal Palace . The fight is nearly the same as the last , but the Mysterious Girl has now instead summoned Leviathan . Leviathan will use Tidal Wave while the Mysterious Girl uses the strong spells she had from the previous fight . Tidal Wave is strong , and it can KO a party member if they have already took a lot of damage . Eventually the Mysterious Girl will cast Osmose on Leviathan two turns in a row , signalling she is preparing to cast Meteor . The same strategy for the first battle fought in the crater still works , but Fusoya should focus more on healing both him and Golbez , and the fight will go quicker without Asura buffing the Mysterious Girl . Haste and Slow help and Shell is also helpful for reducing damage , if Fusoya has a free turn from healing to cast it . Baron Castle . The party the player is given consists of Golbez , Ceodore , Rosa , Rydia , and Edge . The Mysterious Girl retains her powerful magic from previous fights , and can summon Bahamut to use Mega Flare , dealing heavy damage . Though Bahamut will not remain , she can summon him several times if the fight is long enough , and she has substantially higher HP than in previous fights . Ceodore should use Awaken at the start of the fight and use it to its full potential before the effects run out . Rydia and Edge ' s best strategy is to use the Band ability Inferno , which will do around 1 , 500 – 2 , 000 damage to the Mysterious Girl . Golbez ' s best magic to use against her is Flare , if he has learned it . Because Rosa is the only healer that joins the fight , she should use healing spells every turn . If she has learned Curaja from Kain ' s Tale , she should cast it on everybody . Another method is to use Rydia and Rosa ' s Holy Burst Band , with Edge using Healing Pill and Ceodore healing when needed . Ceodore and Rosa can also Band together to use Divine Heal on the party , granting them Shell status to further protect them if the fight occurs during a Full Moon . When the Mysterious Girl nears death , she will attempt to raise her power so she can cast Meteor . This is the party ' s chance to kill her quickly before she attacks , which should not take a lot of damage to do . If the party isn ' t quick enough in killing her , she may summon Asura , Leviathan or Bahamut to aid her . The Depths . Bahamut will be summoned at the start of the fight , and this time the player must target him . Rydia must be in the party or he will begin the battle with Mega Flare , killing the party instantly . The Mysterious Girl uses her magic as in previous battles , and has gained the more powerful Bio , Quake and Tornado spells . Bahamut will count down to Mega Flare each turn . As the countdown ends the Mysterious Girl will cast Black Hole to remove the party ' s buffs , including Shell and Reflect . Thus , the player must simply have their party at a high enough level to survive Mega Flare directly . In the 3D version , one should keep Rosa , Ceodore , or Porom alive . ( Rosa , or Porom are suggested because at that point they should have learned all White Magic spells ) . The party shouldn ' t attack when Bahamut starts counting because the attack bar needs to be filled with white to have enough time to cast Reflect . Right after the Maenad casts Black Hole the party can cast reflect , reflecting Mega Flare . Having Reflect on before Black Hole can reflect the Maenad ' s spells . If the player defeated Asura and Leviathan earlier in the Subterrane and reacquired them for Rydia , they will appear during the fight to call out to Bahamut , and he will return to his senses and attack the Mysterious Girl . After the fight , Rydia will regain him as a summon . If the player did not acquire both Asura and Leviathan , Bahamut must be killed and is lost and the Mysterious Girl will be defeated with him .