The elder daughter of Casterwill was one of Lord Casterwill's children and his first daughter.
History
As a Seeker, Casterwill's first daughter served as the first Lady of the Lake and forged the powerful Willblade. S2E30 She was the first to be bonded with Quetzalcoatl, whose Ring she placed within the Willblade. She later delivered the Willblade to her father so that he could seal the Spiral Mark with the sword. S2E50