Sigrid Guldsdotten is an Avvar mage who has exiled herself from Stone-Bear Hold.
Involvement
Sigrid encounters the Inquisitor during her exile in the Frostback Basin. After meeting Sigrid, speaking to The Augur will reveal that Sigrid has exiled herself because she failed to pass her initiation ritual which would return the Spirit. Examining the site of the ritual reveals Sigrid never completed the ritual because she feared losing the spirit as it was her only true confidante. After exposing Sigrid's deception, Sigrid can be asked to join the Inquisition as an agent. Recruiting her opens A Cultured Exchange war table mission and makes her an agent under Josephine.
Alternatively the Inquisitor can persuade her to return to the Hold and discuss the issue honestly with her mentor, the Augur.
Gallery
Artwork of Sigrid from Heroes of Dragon Age
Artwork of Sigrid's tier progression from Heroes of Dragon Age