Djinn

Djinn (singular: Djinni; ジン Jinn for both singular and plural in the Japanese) are elemental entities of pure Psynergy in the that bolster the capabilities of Adepts. They resided deep within Mt. Aleph until it erupted early in the first, after which they scattered across Weyard.

Overview
Each Djinni is associated with one of the four elements - Venus (Earth), Mars (Fire), Jupiter (Wind), and Mercury (Water) - and also represents, and is named after, a specific aspect that element. Examples include Puff, a Jupiter Djinni, and the Mercury Djinni Steam. Originally, all Djinn of the same element also had the same appearance. As of Golden Sun: Dark Dawn, however, every Djinni is given a unique design; however, the original designs are still sometimes used to represent the Djinn of the corresponding element in general. Like their names, a Djinni's individual appearance is usually related to what that Djinni represents.

While some Djinn are quite easy to obtain and are right out in the open, others hide in the games' overworld. This makes it very difficult for a player that is not assisted by a walkthrough to collect them all. Also, some Djinn must be defeated in battle in order for the player to obtain them while others only need to be interacted with for them to join the party. The ways in which the Djinn affect gameplay in combat, as well as how they contribute to the class system, tends to be a highly discussed subject in review of the Golden Sun franchise.

There are currently 119 different Djinn, with dozens of new Djinn introduced in each game. However, no game has more than 72 Djinn available to the player, and the Djinn available are always split evenly between the four elements. However, due to Dark Dawn featuring new Djinn alongside returning Djinn, this "balance" has been slightly disturbed. Presently, there are 31 Venus Djinn, 30 Mercury Djinn, 30 Mars Djinn, and 28 Jupiter Djinn.

The original Golden Sun had only 28 Djinn (7 per element), while The Lost Age introduced 44 more (11 per element). Data can be transferred between Golden Sun and The Lost Age, allowing players to have a grand total of 72 Djinn in The Lost Age. In Dark Dawn, 36 old Djinn return from the first two games (half of the total Djinn in those games) alongside 47 new Djinn. This technically raises the total Djinn in Dark Dawn to 83, but 11 of them (5 Venus and 6 Mars) are only available for a short while early in the game and cannot be kept, maintaining a limit of 72 "permanent" Djinn.

Mechanics
From a gameplay perspective, Djinn have three different states:

Set
Djinn can be set to any Adept, boosting that Adept's statistics by an amount that varies for each individual Djinni. All set Djinn increase the Adept's HP by a certain amount as well as that Adept's elemental level in the Djinni's element by one. A character's class, and with it their stats and Psynergy, change depending on how many and which elements of Djinn are set to them. When set, a Djinni can be "unleashed" to use their unique ability. Although many are attacks (dependent on the Adept's Attack and often containing additional effects), most of these powers are beneficial in other ways, such as healing, bolstering the party's statistics, or one of a variety of effects truly unique to the Djinni (such as Kite and Aurora).

After being unleashed, Djinn are changed into standby mode. Outside of battle, players can change Djinn between set and standby at will. Players can set a standby Djinni during battle as well, although only one Djinni can be set at a time and it will take up that Adept's action for the turn. After spending enough time in recovery, Djinn are automatically set.

Standby
After being unleashed while set, a Djinni enters standby mode. When Djinn are on standby, they can be used to perform Summons, easily the most powerful attacks in the games. In order to perform any given Summon, enough Djinn of the correct element(s) must be on standby. After the Summon is completed, these Djinn are put into recovery. Outside of battle, players can change Djinn between set and standby at will. Players can set a standby Djinni during battle as well, although only one Djinni can be set at a time and it will take up that Adept's action for the turn. When Djinn are used for a summon, they are chosen in the same order that they were put on Standby. For instance, if five Venus Djinn were unleashed and put on Standby, and then the 4-Djinn summon Judgment was used, the first four Venus Djinn to be unleashed would be used for the summon, with the Djinn which was unleashed fifth remaining on Standby.

Recovery
After being used for a Summon, Djinn enter recovery mode. While recovering, Djinn cannot be traded between Adepts or changed between set and standby. After spending enough time recovering, Djinn automatically set themselves. During battle, one Djinni for each Adept exits recovery at the end of each turn (not counting the turn they entered recovery). Outside of battle, one Djinni for each Adept sets itself after the party travels a certain distance, which is accompanied by a sound effect to let the player know their Djinn have recovered.

Class Changing and Exclusive Psynergy

 * Main Article: Character class

Classes in Golden Sun depend almost entirely on the Djinn set to each Adept. Thus, players are given a choice of how to distribute their Djinn in order to determine their party's class setup. Djinn can all be assigned to Adepts in the party matching their element, or they can be mixed and matched to provide access to a wide variety of different classes. While each Golden Sun game can generally be played through will all Djinn Set onto Adepts of their matching element, this may be difficult to maintain depending on whether all Djinn are obtained, and temporary changes to non-mono-elemental classes are occasionally necessary to access class-exclusive field Psynergy like Growth in certain areas.

Viability
It should be noted that some Djinn's unleash effects in battle can be outclassed by other Djinn which do the same thing, only better. For example, the Djinni Quartz has a 50% chance to revive an adept to 50% of their health; this is less useful than the Djinni Dew, which has an 80% chance to revive an adept to 80% of their health; Dew is further outclassed in TLA by the Djinni Tinder which has a 100% chance to revive a downed adept to 100% of their health. It should be noted though, that while some Djinn might become less useful than a new addition, they still retain tactical usefulness by allowing different classes and characters to use abilities not normally given to them. In the above case, they allow Adepts to access abilities which can revive party members in various classes which don't have access to Revive as a Psynergy.

Regardless of their unleash ability, a Djinni always offers stat bonuses, potential class changes, and participation in Summons, so all Djinn can contribute to at least some extent, and one should never be skipped simply because another Djinni exists which can do the same job a bit better. This redundancy in Djinn unleashes gives the player more flexibility when setting Djinn on standby before entering a boss battle. In the aforementioned example, Quartz can be safely placed on Standby to ensure a quick summon while leaving a more useful/valuable Djinn such as Sap or Bane set to use their more valuable unleash in the battle.

Trivia

 * Early in Golden Sun: Dark Dawn, Isaac and Garet lend Matthew and Karis some of their Djinn. At this point, each of the four Adepts has three Djinn, meaning Isaac and Garet have six Djinn apiece. However, in Golden Sun: The Lost Age, it is possible for each of them to have up to nine. Also, some Djinn from the first game, such as Forge and Vine, are not among their Djinn and must be befriended by the player all over again. It is unknown if the Warriors of Vale released some of their Djinn or if it's canon that they did not collect all of the Djinn in the first two games.
 * It is possible that a number of unseen Djinn were devoured by the Psynergy Vortexes in the Goma Highlands. A child in Carver's Camp remarks on Djinn being formed of pure Psynergy and how his father saw many while working as a lumberjack in the mountains, and then speculates that many of them were eaten by the Vortexes' Psynergy-drawing effect.
 * A glitch in Dark Dawn's Djinn Menu, exploitable with the DS touch screen, can permanently replace an existing Djinni with a glitched Jupiter Djinni named "Moloch". Details are available here.