In chapter 507, what did Eileen mean when she said they are one and the same? I know they are somehow related, but what does it mean when Eileen says she and Erza are one and the same? Is it like what? An Elodas version of Erza? So there would be 3 Erzas now?
Update: Turns out that 


   Eileen is Erza's mother.


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