In battle, when a Weapon Skill is used on an enemy, the target is typically struck with an elemental "resonance" that can result in a Skillchain if a proper subsequent Weapon Skill is used, resulting in additional damage for the subsequent Weapon Skill. Skillchains, in turn, leave the target with another type of resonance that temporarily enables Magic Bursts to be performed, a method for increasing the power and accuracy of offensive magic.
Mage spells (including Blue Mage with the use of Burst Affinity), Ninjutsu, magical Blood Pacts, and Songs can be used at the end of a skillchain to increase damage and accuracy of their magic attacks. This action is called a Magic Burst (MB). In order to create a Magic Burst, the element of the spell must match one of the elements of the Skillchain that precedes it. After approximately 3 seconds after the Weapon Skill that closes the skillchain, there is an approximate 5 second window in which appropriate spells must finish casting in order to produce Magic Bursts.
If multiple Skillchains are being performed with one string of Weapon Skills, it is possible to perform Magic Bursts following each Skillchain that is successfully closed. However, when another Weapon Skill is used following a Skillchain, the target's previous "resonance" will usually be overwritten, thereby closing the current MB window. (Some Weapon Skills do not inflict the target with resonance, however, such as Spirits Within. These Weapon Skills will have no effect on the resonance of a previous Weapon Skill, meaning that they cannot create or "break" Skillchains, and in turn they will not "break" attempts to Magic Burst, either.) In order to MB in between multiple Skillchains, the spell must be completed after the first skillchain has been made, but before the next weapon skill is activated. A subsequent Weapon Skill after the Skillchain will interrupt the window for Magic Bursting, even if it does not create a Skillchain itself. In other words, if a Skillchain has been performed, the next person to use their Weapon Skill may want to wait for a couple seconds to allow MB attempts to finish before using it.
More than one Magic Burst can happen at the same time (i.e. two different people can cast two different spells, as long both spells are the correct element). They will not interfere with each other. Mages can also MB off a Skillchain that they helped create. Dark Knights, Paladins, and Ninjas can do this as well. Note that due to the forced short delay caused after using a Weapon Skill, any player that is both closing the Skillchain and MBing off of it must use a relatively quick spell in order to land the MB in time.
With very careful timing, a single mage can Magic Burst multiple times during the same Skillchain if their subsequent spells cast very quickly. White Mages can double or even triple burst (with perfect timing and Fast Cast) Light with Banish III, Flash, and Holy. Red Mages can easily double-MB, or triple-MB with precise timing, with any kind of magic when utilizing their Two Hour Ability, Chainspell.
Since the Dec. 9, 2004 update, Summoners now have the ability to have their Avatar's magical Blood Pacts act as a Magic Burst. Like above, the Blood Pact must be executed after the Skillchain animation and within 5 seconds afterward, and the Avatar's element must match the skillchain element to Magic Burst.
The same update also allowed Wyvern breath attacks to Magic Burst. However, because breath damage is calculated differently (the primary modifier being the user's HP instead of any other typical stats that modify magic attack power), this does not seem to increase the damage of the breath, but only its accuracy.
Effects of a magic burst
- The update notes say that Wyvern Magic Bursts only give a Magic Accuracy bonus, but Blood Pact Magic Bursts give a damage bonus and an accuracy bonus.
Type of spell to burst
Lv. 1 skillchains
Liquefaction - burst Fire based spells.
Induration - burst Ice based spells.
Detonation - burst Wind based spells.
Scission - burst Earth based spells.
Impaction - burst Lightning based spells.
Reverberation - burst Water based spells.
Transfixion - burst Light based spells.
Compression - burst Dark based spells.
Lv. 2 skillchains
Fusion - burst Fire and Light based spells.
Fragmentation- burst Lightning and Wind based spells.
Distortion - burst Water and Ice based spells.
Gravitation - burst Earth and Dark based spells.
Lv. 3 skillchains
Light - burst Fire, Light, Lightning, and Wind based spells.
Darkness - burst Water, Ice, Earth, and Dark based spells.