Diaga

Diaga (ダディア Dadia) is a recurring spell of the series. It is commonly associated with White Magic.

Final Fantasy
Diaga, also known as HRM3 in the NES release and Dia3 in the Final Fantasy Origins release, is a level 5 White Magic spell, which inflicts a large amount of damage against all undead enemies and has no effect on other types of enemies. In the NES and Origins releases, it inflicts between 80 and 240 damage, while in subsequent releases it inflicts damage depending on the caster's Spirit.

The spell can be bought at Melmond and can be learned by the White Mage and White Wizard job classes. In the Dawn of Souls and 20th Anniversary Edition releases it costs 25 MP to cast.

Final Fantasy XI
Diaga is an Enfeebling Magic spell associated with White Magic. It can be used by Red Mages from level 12 and White Mages from level 18. An upgrade of the spell Dia, it lowers enemies' Defense within the affected area and also deals gradual Light-elemental damage. Uses 12 MP to cast, it takes 1.5 seconds to cast, and 6 for subsequent casting.

The spell can be learned from the Scroll of Diaga, which is sold by merchants in Windurst, San d'Oria, and Bastok for between 1,165 to 1,346 gil.