Dia is automatically learned once reaching level 72. Due to the Aero Mastery II trait, the spell automatically replaces the Aero II spell. The spell will revert back to Aero II when level synced below 72.
Dia deals direct unaspected damage with a potency of 120 when initially performed on the target, followed by a damage-over-time effect with a potency of 60 for 30 seconds.
White Mages should always attempt to place Dia on enemies and bosses at the start of an encounter, and refresh the effect once the previous damage-over-time effect ends. The spell costs 400 MP to cast in PvE content.
In PvP, Dia only inflicts direct damage with a potency of 800 on opposing player characters, and will inflict an increase vulnerability effect on the target for a period of 15 seconds. The spell costs 1000 MP to cast in PvP content.
Behind the scenes
Dia was an ability during the initial launch of the Legacy version. It was a Thaumaturge spell available for use at Rank 12 and it cost 3 action points to set.
Dia II also appeared as a Thaumaturge spell available for use at Rank 36, costing 3 action points to set, and had an MP cost of 30.
The both spells dealt astral-elemental damage over time and reduced the defense of enemies within an area of effect. After the release of patch 1.20, both spells became unusable by any class.
Dia means "day" in Portuguese, Spanish and Occitan.
In ancient Greek religion and folklore, Dia means "heavenly", "divine", or "she who belongs to Zeus". The name is attributed to several figures and treated like an honorific or title.