Galina Zhukovskaya, aka rgtcandy, is not cosplaying here as one of the best characters from The Witcher 3. She has clearly performed some kind of ritual and become the sorceress.
Ciri is Natalia, while photos are by MilliganVick.
Luke Plunkett is a Senior Editor based in Canberra, Australia. He has written a book on cosplay, designed a game about airplanes, and also runs cosplay.kotaku.com.