Summon

Summons are among the most well known and most powerful abilities in the Golden Sun series. A summon allows the player to call upon a powerful spirit to assist them in battle.

Mechanics
Like Psynergy and Unleashes, Summons are aligned with one of the four elements: Venus, Jupiter, Mars and Mercury. Unlike Psynergy, Summons can not be used at will. Instead, the summon is fueled by the usage of Djinn that have been placed in Standby mode. Typically, the element of most of the necessary Djinn will match the elemental alignment of the summon, though some summons also require Djinn of other elements as well. The power of a summon generally correlates with the amount of Djinn needed to fuel the summon. After a Djinni has been used to fuel a summon, it will enter Recovery for a set period of time. Further summons require that the player return Djinn to standby mode.

Each summon, with the exception of the healing summon Coatlicue, has a specific base damage associated with it. However, the total damage potential of a summon also depends on the elemental Power of the summoner and the elemental Resistance and maximum Hit Points of the targets. Summons typically have an unlimited range with unequal damage distribution.

After a successful summon, the elemental power of the summoner will be increased by a specified amount. The amount of increase depends on the number and element of the Djinn used to fuel the summon. Typically, using 1 Djinn of an element will increase the matching Elemental Power by 10, 2 Djinn result in a 30 point increase, 3 Djinn result in a 60 point increase, and 4 or more result in a 100 point increase. However, Adepts can only have one such buff per element at a time, so buffs from multiple Summons will not stack. However, more potent Elemental Power buffs can override weaker ones.

Djinn are selected to be used for Summons in the same order as the order they were put on Standby. For instance, if the player were to summon Thor, which requires 4 Jupiter Djinn, and there were 6 Jupiter Djinn on Standby, the 4 Djinn who were put on Standby earliest (either by being unleashed in battle or by being manually put on Standby out of battle) would be used for the Summon and then put into recovery, while the 2 Djinn who were more recently put on Standby would not be used.

In every game, Summons may be selected even if at the time of selecting there are insufficient Djinn on Standby in order to perform the summon; if other party members unleash the requisite Djinn before the summoner acts - either by having higher Agility or using a Djinni which acts first in the turn - the Summon can still be performed. Additionally, Dark Dawn adds a new feature where any Adept who selects a Summon whose requirements are not yet satisfied will automatically delay their own action during the turn until after the Summon's Djinn requirements have been met, whenever possible, making it easier to use a Summon on the same turn as its Djinn are prepared.

Damage Calculation
Any offensive Summon's damage output is similar to the damage output of an area-of-effect Psynergy; the central target will take an amount of base damage uniquely assigned to the Summon, plus an amount of extra damage equal to a percentage of the target's total HP. This percentage is also uniquely assigned to the Summon. The outcome of this damage will then be raised or lowered depending on whether the caster's Elemental Power for the Summon's element is higher or lower than the target's Resistance for that element. If the user has 20 more Power than the target's marching Resistance value, the Summon would be 10% more damaging to that target. If the target has 30 more Resistance than the user's matching Power value, the Summon would only be 85% as damaging to that target because it would be 15% less damaging.

The same hit will also be dealt to every other enemy on the target's side, but the effective damage output on a given enemy will be cut down proportionally to how many positions away from the target's position that enemy is, just like any area-of-effect Psynergy. However, while the aforementioned Psynergies deal 80% of their overall force to each enemy one position away from the selected target, 60% of their overall force to each enemy two positions away, and then 40%, 20%, and 10%, Summons hit enemies off to the side of the selected target more weakly. The percentages are 70%, 40%, 30%, 20%, and 10%, respectively.

In Golden Sun
Golden Sun features a total of sixteen summons, with each element having four summons. These summons use one to four Djinn of a single element and are available as soon as the party has enough Djinn to use them. However, these summons have no secondary effects.

In The Lost Age
Golden Sun: The Lost Age includes the sixteen regular summons from Golden Sun. However, the game also introduced thirteen new summons, which needed to be specifically acquired by encountering special stone tablets. These summons use Djinn of two different elements and each summon has a special secondary effect. Furthermore, 4 of these thirteen summons can only be acquired after defeating a special superboss.

In Dark Dawn
In Golden Sun: Dark Dawn, all 29 summon spirits from the first two games return, in addition to one new summon spirit, known as Crystallux. The older summon sequences underwent visual changes of varying degrees. Some spirits, such as Moloch remain relatively unchanged, while others, like Ulysses, are radically different to the versions seen in the first two games. When Dark Dawn was first announced, trailers showing some of the summon spirits' animation sequences were released to the public. Many of these clips featured animation sequences that were later altered when the game was released. For instance, the Neptune summon was initially shown to be a whale almost identical in appearance to the whale seen in the first two games, but was later altered to have a darker color and sport horns and markings that were not present on the original version.

For a video exhibition of all 30 summon sequences in the game in sequential order, visit this youtube video.