Crystal room Crystal rooms , also known as crystal chambers , peristylia , and crystal sanctums , are recurring areas in the " Final Fantasy " series . They consist of a floor with an altar that holds a Crystal , usually the last floor of a dungeon or shrine built for the sole reason to protect them . Typically the musical theme of the crystal rooms is the " Prelude " , and behind the Crystal a Warp portal often grants access to the outside of the location . Appearances . " Final Fantasy " . Each of the four elemental Crystals are in a dungeon related to the Crystal ' s element : the Earth Crystal is in the Cavern of Earth , the Fire Crystal is in Mount Gulg , the Water Crystal is in the Sunken Shrine , and the Wind Crystal is in the Flying Fortress . Each of the Four Fiends take residence in these spots , respectively to the Crystal they are draining energy from . " Final Fantasy III " . There are four dungeons that hold altars for the Crystals , of which two have clear elemental properties : the Wind Crystal was kept in the Altar Cave , the Fire Crystal is kept in the Molten Cave , the Water Crystal is kept in the Cave of Tides , and the Earth Crystal is held at the Ancients ' Maze . Similar to the original " Final Fantasy " , three minions of Xande have captured three of the Crystals , the Fire Crystal being the exception . Kraken , Titan , and the Land Turtle attempt to nullify the influence of the Crystals in the world . " Final Fantasy IV " . In the Mysidian crystal room the forces of Baron attempt to collect the city ' s Water Crystal for their nation ' s own use . In truth , and unlike the previous games , there are ten or more crystal rooms in " Final Fantasy IV " , though most are not visited , as sixteen Crystals exist : four of the Overworld , four of Underworld , and eight Lunarian crystals on the Red Moon . In the Overworld , crystal rooms can be found in Damcyan , which housed the Fire Crystal , Troia , where the Earth Crystal formerly resided , Fabul , once home to the Wind Crystal , Mysidia , as aforementioned , and in the Lodestone Cavern , where the Dark Elf absconded to with the Earth Crystal from Troia . In the Underworld , two crystal rooms can be visited : the one at the Dwarven Castle and the one at the Sealed Cave . The unseen Tower of Babil crystal room houses Golbez ' s seven stolen crystals . Finally , in the Red Moon , the room that holds the eight Lunarian Crystals can be visited in the Crystal Palace . This room houses the portal that leads deep into the Lunar Subterrane , the game ' s penultimate dungeon . " Final Fantasy IV - Interlude - " . The player can visit three Crystal Chambers wherein the Crystals silently shed their light . In Damcyan , the player can see the Fire Crystal with Palom and Porom , now housed in a crystal room behind Edward ' s throne . In Fabul , the player can visit the Wind Crystal when they arrive . In the Sealed Cave , the player can see a Dark Crystal with Rydia collapsed before it , in a scene which begins the " Interlude " . Crystal Chambers reappear in the sequel as the resting places of the Crystals . " Final Fantasy V " . The four crystal rooms are located in shrines and castles , and possess machinery that increase the Crystals ' power , developed by Cid Previa , with exception of the Ronka Ruins . The Wind Crystal is in the Wind Shrine , the Fire Crystal is in the Karnak Castle , the Water Crystal is in the Walse Tower , and the Earth Crystal is in the Ronka Ruins . At the end of the game , the Crystals are reformed and relocated : The Earth Crystal at the Pyramid of Moore , the Wind Crystal at the Island Shrine , the Water Crystal at Istory Falls , and the Fire Crystal at the Great Sea Trench . The main antagonist , Exdeath , uses his nefarious influence to destroy the Crystals with his powers of darkness . The Liquid Flame and a Karnak soldier attack the Fire Crystal , King Tycoon attacks the Earth Crystal , and a Garula attacks the Water Crystal . " Final Fantasy XV " . Lucis ' s Crystal Chamber is located in Insomnia and appears to also host a throne . The Chamber is dimly lit , and its floor is layered with a sheet of water . The Chamber ' s layout resembles that of a masonry dome , and at its center lies a large Crystal . This is constantly lit by grounded searchlights and a center oculus . " Final Fantasy Tactics Advance " . Marche goes into five types of crystal rooms via a black seam . Each crystal room has a crystal which is guarded by a Totema . " Final Fantasy Type - 0 " . The places where the four Crystals of Orience are housed are called peristylia . The peristylium of the Vermilion Bird Crystal is at the Sorcery Division ' s quarters in Akademeia , and usually only the Crystal ' s l ' Cie and the archsorceress Arecia Al - Rashia visit it . The room is entered via a magic portal , and is circular with cogs and gears on the background , the Crystal floating atop a pedestal . The other peristylia are presumably similar , but only the White Peristylium is seen . Unlike the Vermilion Bird Crystal , the White Tiger Crystal is locked inside a machine that subjugates it . " Bravely Default " . The crystal room refers to the place in each of the Fire , Wind , Water and Earth Temples that harbors their respective Crystals . The vestal s attends the Crystals and pray to it in the room specifically and exclusively . Musical themes . The most recurring track heard in the crystal rooms throughout the series is the " Prelude " . " Final Fantasy III " stands away of this rule , having a special " crystal room " theme to play in all four crystal rooms . It is also notable that the Altar Cave , Molten Cave , Cave of Tides , and Ancients ' Maze all have " Into the Crystal Cave " as a background music .