Aqua is one of the main protagonists of Kingdom Hearts Birth by Sleep. She is one of the Keyblade Wielders before Sora. Like Terra and Ventus, it's her dream to become a Keyblade Master, a dream she alone was able to accomplish from the three.
Her name is Latin for "water", while Kairi's name in Japanese means "sea". The only connection between the two is that Aqua met Kairi in Radiant Garden in Kingdom Hearts Birth by Sleep and put a protective spell on her necklace, which later brought Kairi to Destiny Islands. Kairi, by accidentally touching Aqua's Keyblade during this time, also inherited the Keyblade from Aqua.
- Aqua will guest star in Pooh's Adventures in Pompeii.
- In the Jeffrey & Friends' Adventures series, Jeffrey will fall in love with Aqua. Eventually, she'll become his girlfriend. Some time later, Aqua will marry Jeffrey, and become Xion's adopted mother.