The Eternal Queen is the current ruler of the Kingdom of Zephilia.
She is a human, who, similarly to the Knight of Aqualord, was born with a fragment of the late Aqualord Ragradia within her soul. This seems to give her an amount of the shinzoku's abilities, which is the most apparent in her lack of (or greatly reduced) aging, which might serve as the origin of her title as well. The source material suggests that she is acting as the queen of the country since a while now, although the exact length of her rule was never elaborated upon. Unlike the knights, she seems to have inherited access to the Aqualord's knowledge, instead of possessing a greater amount of the shinzoku's magical power. (Still, she might not have the same amount of knowledge that is contained in the Claire Bible - the sources seem conflicting in this regard.)
When planning Slayers NEXT, Kanzaka forgot to mention his concept of the Eternal Queen, and thus the anime crew created a very similar character instead. This was Auntie Aqua, who, as the manifestation of the Aqualord's remaining thoughts, is able to appear near the complete copies of (and also the original) Claire Bible.
- ↑ Q: "I hear that they call the queen of Zeffiria as 'the Eternal Queen'. Lina described the people in Zeffiria are so powerful as to 'make allowance for a blow, still the blow can break a rock', and the queen of Zeffiria rules the nation so well that there are no bad rumors about the nation. I wonder what is the queen? I wonder that she can be something like a Ceiphied Knight and she is extremely powerful. Am I right?"
A: Well, she is Aqualord Ragradia. In TV anime, there is another character for the dragon lord.
M: ... What? ...
A: The memory of Aqualord is in the warped space as the Claire Bible, but other pieces, power, abilitiy, and something like that are in the queen of Zeffiria.
M: Does she has, or succeeded the power of the dragon lord?
A: Yes, she succeeded a part of the Aqualord's ability, not all of them. Therefore, she can't be powerful as the Aqualord was. She can't match with Lina's sister, neither. Anyway, she has lived so long.
M: Is she an old lady?
A: Not so old, and she is a beautiful lady.
- from an interview with Hajime Kanzaka