Nimue is lovely, and does look a bit like Violet. But then again, Arthur looks a bit like Hook. Her dress has a rose floral pattern. More RODs (roses of doom) — this definitely doesn’t spell anything good for Merlue (Nimlin?)
She seems to be wearing some pendant cleverly concealed by her hair. I wonder if that’s going to be significant in some way?
Masked Dark One appears to have a rather strong chin, so I doubt it’s Nimue. I wonder what the significance of the mask’s design is, if any.