She started as a servant of an ancient kingdom who has magic power to turn any kind of water into the purest water one can ever see. At one point, a plague ravaged the kingdom and the king and everyone blames her magic power bringing misfortune.
She was to be sacrificed to a God of the sea (truly is a huge ancient water serpent) but the tide turned in her favor as the Sea God demolished everyone but her and even bent to her will. That is how the legend of Aquarius was born.
*sorry for the messy story lol