Aqua is the last known living disciple of Master Eraqus, so far at least, with Terra being seemingly gone due to Xehanort’s plans and Ventus having gone into deep slumber due to Vanitas’s take over of his body. The three of them were good friends.
Aqua is not much of a melee fighter but more of a gifted mage. Her knowledge of magic seems to be limitless as are her skills with the Keyblade. Hope traveled with Aqua for awhile on her mission to eliminate the Unversed.
Afer the battle at the Keyblade Graveyard, it was Apparent to Aqua that she belonged with hope, seeing as how everyone she was close with was now gone. She now trains Twilight as a keyblade master since she acquired one after battling a Vanitas possessed Ventus.
Currently, she is proctoring Twilights test as she soon travels Alola.