"Speed party Djinn recovery with Sol's light."
Aurora is a Mars Djinni found in Golden Sun: Dark Dawn. Aurora is found in the final dungeon of the game, Apollo Sanctum, as an optional collectible at an otherwise mandatory puzzle comprising the Venus area of the dungeon.
When Aurora is unleashed in battle, a unique effect instantly causes all of the current battling party members to go through one extra turn's worth of Djinn recovery time. The passing of a turn's worth of Djinn recovery time that transpires at the end of a given turn is unaffected, meaning that two Djinn in Recovery on each Adept will be re-Set this turn instead of just one when Aurora is used.
In Dark Dawn, Aurora's unleash animation visually resembles the user summoning the 3D model of Aurora far above the party while the camera zooms out, and the Djinni exudes a luminous radiance like the sun itself for a brief period. Then the radiance vanishes and Aurora flies far above the party while the party is mostly engulfed in a red beam of life with a flame covering the center two party members. Aurora floats off the time as the beam and its flame narrow and shrink out, and the battle scene is returned to normal.
Golden Sun: Dark Dawn: Aurora is found in the final dungeon of the game, Apollo Sanctum, as an optional collectible at an otherwise mandatory puzzle comprising the Venus area of the dungeon. It is at lower right end of the screen, in a corner that can only be reached by making a white spire appear out of its hole in the wall left of it, and then cast Grip on it to swing across it to where Aurora is.
General: Aurora is a unique effect that allows you to have 2 recovering Djinn re-Set themselves in a particular turn rather than just the traditional 1. This is meant to be used to help the party regain their higher-tier classes quicker after the party has used up a lot of multi-Djinn summons. Another interesting use for Aurora is to allow another Djinni to recover in the same turn it is used for summoning; if another Djinni is unleashed and summoned with before Aurora is used, it will recover at the end of the turn, allowing it to be unleashed again immediately. While this exercise cannot be continued indefinitely (Aurora is placed on standby as a result), it can provide your battling party with two turns of Chasm's protection, among other things, as well as the obvious benefits that come with whatever summon was used. In The Lost Age, the Mercury Djinni Eddy is this Djinni's identical equivalent.
Golden Sun: Dark Dawn: Being available in the final dungeon of the game makes this the very last Djinni a player typically adds to their collection in the game, meaning the very end of the game is the only opportunity Aurora has to be used. This is not necessarily a bad thing, though, because a couple bosses at the end of the game do have the capacity to make unleashing Aurora productive for you. The optional boss battle against Dullahan is one example of a battle where Aurora would theoretically be put to use; it has the Djinn Storm ability that puts all nine Djinn of every party member on Recovery mode; provided Aurora isn't one of the Djinn drained by this effect (you would have it set on one of the Adepts in the reserve party in these cases, then switch the reserve member in after the Djinn storm), it can help a fully drained party get back on its feet a turn faster, which may mean the difference between survival and defeat.
Aurora is probably at its most practical in the final boss battle, though, because the boss has the single-target version of the move, Djinn Blast, putting all nine of one Adept's Djinn in Recovery. As this is both a mandatory battle and a difficult one, Djinn Blast constitutes a very real threat to the likelihood that you will win the game; one of your best Adepts can be crippled for many turns due to their class being lowered all the way down. If you cannot replace this Adept for a while by switching in another from the back row, Aurora can be used to make that Adept's Djinn recovery go forward two measures instead of one. This can guarantee that the Adept will raise themselves one class stage within just a turn, and this increase in all of the Adept's statistics can make a great difference. Aurora's effect will be greater if your current battling party happens to have more than one Adept with Djinn on Recovery. At any rate, Aurora should be placed on an Adept you know you are going to use for supporting the party more than for dealing damage.