Both Brannagh and Dagdan are described by Feyre to be quite alike their uncle. Attractive in appearance and vacant of all emotion, Brannagh is haughty and cruel, enjoying only the company of her twin brother.
Brannagh and her brother, alongside Jurian, reside in the Spring Court in the home of their hesitant ally, Tamlin, as emissaries from Hybern. During their stay in the Spring Court, the daemati pair examine the weakness of The Wall, as well as the weaknesses of the Spring Court, which is ripe for invading. They poison the inhabitants of the Spring Court with faebane, including Feyre. The twins do not buy Feyre's horrific tale of torture at the hands of Rhysand, and keep a wary eye on her. In the end, they seek to capture her and return to Hybern with her in tow, but the faebane had not yet taken its toll on Feyre and, with Lucien's help, Feyre defeats them in combat, beheading Brannagh and slaying Dagdan.