There are none who can stop me in all of creation! You, too shall fall before me!
Ahriman is an enemy in the Dawn of Souls and Anniversary versions of the original Final Fantasy. It is a flying creature encountered by the Warriors of Light in the bowels of the Earthgift Shrine, along with the other cameo bosses from Final Fantasy III. This winged, one-eyed beast inhabits the northeast corner of the Shrine's final floor.
Ahriman is the most difficult boss on the final floor. Ahriman uses the Earthquake attack, which can instantly KO party members. The Ahriman also uses Blaze, Thunderbolt and Icestorm, all of which can deal more than 300 damage to the entire party. Ahriman has negligible physical attack that inflicts minor damage. He can also heal himself (almost 200 HP) with Cura.
Ahriman is best saved until the party is level 45 or higher. Ribbons and NulDeath/NulAll will guard against its Earthquake. Because Earthquake is considered an Earth-elemental attack, and not a Death-elemental attack, Protect Rings will not provide resistance to it (unlike what the ingame description may suggest). Even without resistance, higher level parties can avoid it fairly reliably thanks to their natural Magic Defense, with the White and Black Wizard boasting the highest Magic Defense growth of the classes.
Its other elemental attacks are not used as frequently as Earthquake, but it is still best to have the White Wizard cast Healaga to patch up the damage. A Sleepra spell, cast by a Black Wizard, is potent enough for the effect to stick.