In the original version it has the maximum Effect Capacity, which means no other spell or technick can be performed simultaneously. The spell can be obtained from Arcane Magick 7 license for 105 LP. The spell can only be purchased in Balfonheim Port for 9,400 gil after the events in Giruvegan.
In the Zodiac versions, the Arcane Magick licenses have been reduced to three. Dark and Darkra are both Arcane Magick 1 License, which costs 40 LP, and Death and Darkga can be bought from Arcane 2 License, and cost 50 LP, while Arcane 3 License can be purchased for 120 LP, which contains Ardor. It can be used by the Red Battlemage. Darkga is bought from Balfonheim after the events in Draklor Laboratory, and found in a treasure in Trial Mode Stage 87 with the Diamond Armlet equipped.
Darkga is not accessible to the player, but is part of the Dark Magick skillset used by Ghost enemies.
Darkaga is a high level Black Magic spell. The spell costs 4 AP to cast and it has a spell power of 15. It can only be used if the Darkaga Tome item is in the character's inventory. The spell can only be purchased in Invidia for 5,000 gil. A Darkaga Tome can also be found in a chest inside the Magic Laboratory.
Darkga I-III are magic attacks available only for Jornee to use. The spells can only be learned from her first Succubus signet. All Darkga spells deal heavy dark-elemental magic damage to a single enemy and cost 45 MP.
In the original free-to-play versions, Darkga I-III could be used by any party member equipped with a Darkga version of the Succubus or the Cloud of Darkness OR signets. Each version of the spell dealt more damage depending on the summon's rank and had increased MP costs for each version of the spell.
The default Darkga is an enemy ability used by multiple Final Fantasy XII enemies. In addition, Ultimate Darkga is an ability usable by multiple event bosses, the effects varies on the boss using the spell. Lastly, Savage Darkga is an ability used exclusively by Deathgaze (Savage), dealing massive dark-elemental damage to all party members and lowering their dark-resistance by 2 levels.
Etém's Darkga deals magic dark-elemental damage once to a single enemy. It has a 10% chance of being used by Etém when its magicite is at its initial rank, however this raises to 70% after being fully maxed in rank.
Deathgaze's Darkga deals massive magic dark-elemental damage once to a single enemy. being able to break the damage cap. It has a 10% chance of being used by Deathgaze when its magicite is at its initial rank, however this raises to 100% after being fully maxed to level 99.