Mist is but one of the manifestations of magic energy throughout the series, and can be compared to the power of elemental crystals in early Final Fantasy games, Lifestream in Compilation of Final Fantasy VII, pyreflies in Final Fantasy X, crystal energy in the Fabula Nova Crystallis: Final Fantasy series, and Miasma, the poisonous substance in Final Fantasy Crystal Chronicles that is a source of monsters, and that appears in sparse locations of Final Fantasy XI as a type of impassable barrier.
Though not specifically referred to as Mist, the Four Fiends sent elemental energy in the form of four streams of colored mist from their respective shrines to the Chaos Shrine. The Warriors of Light can view this phenomenon from onboard the Flying Fortress. The mist's power allowed Garland to travel back in time.
The Mist Cave and the Valley of Mist beyond it are shrouded in thick white mist. Cecil and Kain journey through the cave to the valley, and a Mist Dragon forms from the mist to bar their way. They later discover a Summoner in the village of Mist conjured the dragon and the mist to ward off travelers and protect the village.
In the Advance release, Rydia's trial in the Lunar Ruins involves her reverting to her child form, and her summons leaving her in a cave full of mist that obscures the player's view. After retrieving her summons and finding the cave exit, the Lunar Dragon forms from the mist and attacks.
Mist is residual element of the souls that should return to the planet, but is discharged into the atmosphere instead. According to the Final Fantasy IX Ultimania, mist appeared around 800 years ago. Garland unleashed the mist upon Gaia to disrupt its people so that Terra could one day be reborn.
Mist is distributed through the Iifa Tree's roots and is in fact the Gaian souls being refused to return to their crystal and expelled to flow back into Gaia's atmosphere instead. These stagnant and tormented souls are reborn as monsters. Mist is found primarily on the Mist Continent, where its effect causes many of the kingdoms to retreat to higher elevations. The power of the mist also hardens hearts, provoking conflicts around the continent.
The people of the Mist Continent, and in particular the city of Lindblum, have developed mist-powered engines, which are primarily used to power airships. However, this means airships will only function where there is mist, meaning they can't fly outside of the Mist Continent. Additionally, the cable cars within the Aerbs Mountains are also mist-powered. Kuja taught Queen Brahne to manufacture black mages from the mist and also claims he can make Mistodons from it.
After Zidane and his party defeat the Soulcage at Iifa Tree's base, mist production stops for a time. However, after Kuja discovers his Trance powers and destroys Terra, Iifa Tree activates and Mist is expelled onto the entire world. After the Iifa Tree settles following Kuja's defeat, the world is finally freed from its scourge.
Mist is the source of magick in Ivalice, and a major plot device and gameplay feature. When densely concentrated, it becomes visible as fog. Mist gathers in both living beings and stones called magicite. Anyone, either wielding these stones or not, can extract Mist to use magick. A form of magicite, nethicite, absorbs Mist, thus nullifying any magick effects. If deifacted nethicite absorbs too much Mist, it will release it suddenly if someone tries to extract it, resulting in a violent explosion. Manufacted nethicite cannot handle too much Mist, simply shattering if it absorbs too much.
Mist continues to become the source of magick in Ivalice. When one is about to cast a spell, they must wait for mist to build up before they can do so. Usually, this restoration amounts to 10 MP unless effected by an outside force, such as a Clan Privilege.
Mist also serves as one of the four possible weather conditions. The magick is characterized as a billowing golden fog that can breed various strains of monsters and imbue weaker beings with adverse effects. Mist is especially prevalent at the Aldanna Range and Zellea, the Forbidden Land. The Geomancer's Mist Storm can only be used when the mist is active.
Mist is an ability exclusive to the Misterian race, which Makenshi and Madoushi belong to. It is created from their bodies in the form of their breath, and thus they wear masks to control the amount they release. They keep a stock in bottles around their waists, and use them to summon Sword Dragons.
Mist is a phenomenon caused by small droplets of water suspended in air.