Iris

Iris is a Summon sequence of the Mars element found only in a password-enhanced game of Golden Sun: The Lost Age. It is the ultimate Mars summon and is widely considered the ultimate move – Psynergy, Summon, Weapon Unleash, Monster Skill, and otherwise. When nine Mars Djinn and four Mercury Djinn are on standby, and Iris’s Summon Tablet has been collected, the Iris Summon sequence can be activated. It resembles a matriarchal goddess garbed in a divinely textured array of clothing summon up the battle’s foes and project them into outer space, where they are sent into the blaze of the Sun itself.

Iris has an intimidating base Mars power of 800 and also does additional damage equivalent to 40% of the enemy’s maximum HP. In addition, all eight Adepts are revived and have their HP meters completely cured. Iris, however, is not automatically summonable once one collects the required Djinn. Iris can only be summoned once the Summon Tablet containing the sequence has been found at the end of Anemos Sanctum near the end of the game; only with all 72 Djinn collected does the dungeon open up, and only when players pass the seemingly overwhelming challenge presented by the undeniably fearsome superboss Dullahan can they access this summon.

Iris is undoubtedly the game’s ultimate Summon sequence and is certainly the game's strongest Mars-based attack, much stronger than even Charon. The extreme Djinn requirement, along with the lack of bosses to fight in The Lost Age at the point in time Iris would be attained, means that there is scarcely an opportunity for Iris to be put to very practical use as its only real use is as a "trump card" from when the team is failing badly (with the exception of battle mode); Iris is more meant as a “bragging rights” summon for players who have conquered The Lost Age's ultimate challenge in Anemos Sanctum, and actual uses of the summon are mainly for show. The power of the attack as well as the amazing regenerative effect on the whole party may make it a very useful summon to use in the later stages of the Doom Dragon final boss battle, provided the player goes into the battle with summoning Iris set as a clear objective.

Trivia

 * Interestingly, Iris was referenced to in the first Golden Sun, when Isaac and his party climbed the Mercury Lighthouse in pursuit of Saturos and Menardi. The final waterfall passage leading to the Mercury Lighthouse's beacon is activated by casting Ply on the Aquarius statue. This message appears as a hint to the player: "He who honors (ply) the goddess of rainbows (Iris) shall be guided to the heavens upon wings of fluid grace."

Cultural Allusions
Origin: Greece

Iris in Greek mythology was the personification of the rainbow and was the messenger of the goddess Hera, who was the queen of the gods. The Mars and Mercury Djinn as the Djinn used to summon her are well-placed, as the rainbow only appears when the Sun (Mars) breaks through the clouds after a rainstorm (Mercury).