Aqua is one of the main protagonists of Kingdom Hearts Birth by Sleep. She is also the protagonist of Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-, and is playable in a single fight in Kingdom Hearts III. Aqua was a Keyblade wielder years before Sora was. Like Terra and Ventus, it is her dream to become a Keyblade Master, a dream she is the only one of the three to accomplish.
