Could be very well the Queen herself. After she left Lothric and went to Anor Londo, back to where she came from to escape her husbands madness, Sulyvahn turned her into one of his killing machines, the boreal knights, and send her back. The healing miracle Soothing Sunlight we gain from transposing her soul is the most powerfull in DS3 with even a mentioning of Gwynevere. The god mother. Many though that means the dancer is Gwynevere herself but it's rather meant to implicate how royal the dancer was. She was a first class princess of Anor Londo having this miracle bestowed! Someone you would marry to a great king of a great kingdom. Oceiros The king of Lothric.