Magestone

The Magestone is a Dragonstone that appears in Fire Emblem: Ankoku Ryū to Hikari no Tsurugi, as well as its sequal and remake. It also appears as an unused item in Fire Emblem: Fūin no Tsurugi. It allows the user to transform into a Mage Dragon, granting them a magic-based attack as well as an immunity to taking damage from magic. It has infinite uses in the original game and 30 uses in Fire Emblem: Shadow Dragon. It is often an enemy only weapon, although one can be bought in the Secret Shop in Fire Emblem: Monshō no Nazo.