Sorceress Sellen is a character in Elden Ring. She is first found locked away within the bowels of the Waypoint Ruins. The Tarnished can choose to study magic under her tutelage, allowing them to buy spells from her.
The form you see in Waypoint Ruins is just a projection, as her true self is held prisoner in a the Witchbane Ruins. If the Tarnish chooses to help her, she will ask them to put her Primal Glintstone into a new body. The Tarnish can choose to continue to help, or fight her, at the end of her questline. In either case, she ends up with a terrible fate. Should the player help her, she is transformed, along with her fellow conspirators, into a school of graven mages, where she is barely able to speak.
