Dia (ability)

Dia (ディア Dia) is a recurring spell in the Final Fantasy series. It is a White Magic spell, albeit with different effects in different games.

Final Fantasy
Dia, also known as HARM in the NES release and Dia1 in the Origins release, is a level 1 White Magic spell which inflicts minor damage against all Undead enemies. It has no effect on other types of enemies. In the Famicom and Origins releases, it inflicts between 20 and 80 damage, while in subsequent releases, it inflicts damage depending on the caster's Spirit.

The spell can be bought while in Cornelia 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 5 MP to cast.

Final Fantasy XI
Dia is an Enfeebling Magic spell in Final Fantasy XI that can be cast by Red Mages and White Mages starting at level 1 and 3 respectively. It is used primarily to lower the Defense of a targeted creature, but also does do very insignificant Light-elemental damage over time. There are subsequent levels: Dia II, Dia III, and an area version named Diaga. Dia will do 1 damage per tick, Dia II will do 2 per tick, and Dia III will do 3 damage per tick.

Trivia

 * A character from Final Fantasy XIII, named Vanille, shares her clan name with the spell.

Etymology
"Dia" is the Spanish word for "day", which explains the "rays" of the sun shining upon the enemies once it is cast.