Why exactly was it so powerful? Is it just because it had foresight and could tell the user about the future?
P.S i liked the fact that Freya could use Ravenna as the mirror to find out what happened to her baby
The most logical explanation would be, that it isn't from this realm. Imagine a world/realm where there is only magic. Imagine that a person from that realm tries to get over to another realm via a mirror technique and fails spectacular. Now the most powerful entity is trapped inside a mirror.
It is never explained where it is from orginally afaik.
"The end is not the end, but for the beginning an end is always near."
It just seemed to screw with Ravenna by making her paranoid and telling her how Snow White and Freya's daughter would surpass her
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