Elemental Affinity

Elemental Affinity is an ability or trait present in some pieces of equipment in the series, which enhances the elemental damage dealt by the user.

Final Fantasy V
Several pieces of equipment in the game increase the power of elemental attacks by +50%.

The bonus is applied before subtracting the opponent's Magic Defense.

Final Fantasy XI
A variety of staves offer different levels of elemental affinity in Final Fantasy XI. In addition to increasing the damage dealt by appropriate spells, affinity also improves casting accuracy and reduces the recurring cost of a summoner's elementally-aligned pets. The hidden downside is that spells of the element weak to the affinity become less powerful and more likely to miss. A summoner also spends greater MP sustaining a pet that suffers from the equipped element.

These penalties are the inverse of the benefits that the affinity would normally grant. For example, Neptune's Staff, with tier 2 water affinity, strengthens Flood by 15% with 30 bonus accuracy but increases the cost of using Ifrit, whose fire is vulnerable to water, by 3 MP every 3 seconds. This contributes to the popular practice of switching staves for each spell that a mage employs.

Customizable staves available at high levels provide an opportunity to improve one aspect of affinity at the cost of another. One augmented item may offer more damage, less accuracy, and no reduction in perpetuation cost while another offers only a large perpetuation benefit. Advanced customizations further improve affinity with a reduction in casting time for aligned spells.

Final Fantasy XII
When a character equips a weapon or armor that has an elemental affinity, all damage, both physical and magickal, associated with the element, is boosted by 50%. The affinity bonus is independent of the weapon's own element, in that the bonus usually exists on its own and elemental weapons usually don't have an elemental affinity.

For example, none of the staves that have the elemental affinity trait has an element in the weapon. Instead, the user benefits from the affinity by casting magick of the element the weapon gives a bonus for, but there is no bonus for physically attacking with said weapon as the damage with physical attacks is non-elemental.

In the original version of Final Fantasy XII, all ninja swords have the element of Dark, but none has an elemental affinity on the Dark element. In order to apply the elemental affinity to ninja swords, the character must wear the Black Robes armor, which gives a +50% boost to Dark elemental damage, making all attacks dealt with ninja swords +50% the normal damage. This is no longer the case in the International Zodiac Job System as most of them have their element changed and only the Yagyu Darkblade retained its original dark element. Also, since the can not equip the Black Robes, they can not benefit from the damage boost.

Holy Rod is the only weapon that is both elemental and has an elemental affinity; its Holy element is strengthened by its Holy affinity, so all physical attacks will be 50% more powerful, compensating for the weapon's fairly low attack power. The effect is even greater against enemies that are weak against Holy, as they will take double damage from Holy, plus the +50% bonus.

Potentially the greatest damage increase is dealt to an oiled enemy through the casting of a fire elemental spell while equipped with the Flame Staff or attacking it while equipped with the Burning Bow and Fiery Arrow, as oiled targets take triple the normal damage from Fire-elemental attacks. Elemental affinities do not stack, so there is no benefit in equipping two pieces of equipment that give an affinity to the same element simultaneously.

Final Fantasy XIII
Fire Affinity, Frost Affinity, Lightning Affinity, Water Affinity, Wind Affinity and Earth Affinity increase the damage dealt by the user's corresponding elemental attacks and exist as passive abilities in equipment. The bonus is between +20% - 50%, depending on the affinity's strength.

Final Fantasy Tactics
There are several types of equipment found in the game that increases the power of elemental attacks.

Final Fantasy Legend II
There are four MAGI found in the game that augments the power of elemental abilities.

Final Fantasy: The 4 Heroes of Light
The Elementalist's job abilities Augment and Amplify enhance the effects of allies' elemental attacks and last four turns.