Treasure Isle

Treasure Isle is an optional dungeon-style location found way out near the top of the Great Eastern Sea in Golden Sun: The Lost Age. It is essentially two dungeons in a row, with one much harder and accessible much later than the other; the easier first part can be explored as soon as Felix gets the Grindstone and its Grind Psynergy in Lemuria. The later part can only be explored after the Reunion, when Isaac's party joins up with all their own Utility Psynergy items, including the Lifting Gem and its Lift Psynergy. Among the stronger equipment are the Iris Robe and the Fire Brand, and at the end of the dungeon is one of the most dangerous opponents in the entire series to battle, the Star Magician, who guards the Summon Tablet for the Azul Summon sequence.