"From the stars and the crescent moon, a queen of light, ruled this rambling place. Each night she walked the palace alone, her luminosity dawn's own face."
The Queen of Light was the ruler of Lemuria before she suddenly disappears one day, allowing the Black Queen and her two daughters to conquer Lemuria with dark creatures.
The Queen of Light is Aurora's mother.
In Aurora's flashback she is fine, then feels "sick" and dies (actually poisoned by the Queen of the Night)
However, she reappears at Aurora before the final battle against Umbra. And she replaced Rebella!