Rusty Sword

The Rusty Sword is a recurring weapon in the Mana series, and it first appears in Final Fantasy Adventure. As its name suggests, the Rusty Sword is a blade encrusted with iron oxide that often does negligible damage to foes. It is frequently the weakest sword where it appears, and so is at worst a joke weapon. However, in the hands of a skilled blacksmith or with divine assistance, the rust can be stripped in order to reforge the blade into a stronger weapon.

Final Fantasy Adventure / Adventures of Mana
In Final Fantasy Adventure and its remake Adventures of Mana, the Rusty Sword is obtained after defeating Ifrit in the Undersea Volcano. Following the trip through the Sanctuary of Mana, Sumo will witness one final vision of Fuji's mother. As he presents the blade, it transforms into Excalibur, the strongest sword in the game.

Secret of Mana
In Secret of Mana, Randi begins his journey by pulling a Rusty Sword out from a stone in the falls near Potos Village. The Rusty Sword is the unmodified form of the Mana Sword as it comes into Randi's possession.