The Eternal Forest's Chanting

She is a mysterious elven girl who spoke to Kiriya through dreams. She is later revealed to be the spirit of Celestia, the elven queen of Astraea, whose cells were used to create Xecty. With her help, Xecty becomes the priestess of Astraea's Tower of the Wind. She decides to be with her brother, the soul of the liberated Killrain, and they are sealed together in the other dimension.

She bears a strong resemblance to Elwyn.

source: wikipedia