Blk Mag (Final Fantasy IX)

Blk Mag is Vivi Ornitier's skillset allowing him to use Black Magic spells. If Steiner is also in the party, Vivi's Black Magic can be used as part of his Sword Magic. In Trance Vivi's Blk Mag turns into Dbl Blk that allows Vivi to cast two spells per turn.

Black Magic spells include offensive elemental and non-elemental spells, and spells that inflict status ailments. If damaging used against multiple enemies, it will deal half the damage (if damaging spell) or infliction rate (if status spell) to each enemy, regardless of the number of enemies. Blk Mag command is sealed in Oeilvert.

Mechanics
Black Magic is learned from equipment by accumulating Ability Points in battle.

Black Magic spells with the exception of Osmose, Demi, Comet, and Meteor, follow the following formula in computing damage:
 * $$Base = Spell Power - Target's Magic Defense$$
 * $$Bonus = Mag ... [(Lv + Mag) / 8] + Mag$$
 * $$Damage = Base * Bonus$$

Bonus is halved by Shell, being under Mini and if the player multi-targets the spell (unless the spell is naturally multi-target).

For status spells the formula is:
 * $$Chance = Spell Accuracy + Lv + [Mag / 4] - Target's Level$$

After which two random numbers are used to determine if the spell will hit.


 * If (1st RN mod 100) >= Chance, attack misses
 * If (2nd RN mod 100) < Target's Magic Evade, attack misses

In Trance Blk Mag turns into Dbl Blk where Vivi can casts two spells on his turn. The spells cost MP and expend the Trance gauge independently. Occasionally, enemies can take turns in between the first and second cast.

Vivi can use the Focus ability to increase his magic power. Vivi can stack the effect but once the Magic stat reaches 99, it will not increase further. The effect lasts for the entire battle, even if KOed.

The formula for Focus is as follows:
 * $$[Magic * 1.25]$$