Adda the White was the daughter of Foltest, king of Temeria. She was born a striga as a result of a curse cast by Ostrit, a local magnate who loved her mother, Adda of Temeria. When he learned of the incestuous relationship between the king and his sister, Ostrit tried to put a curse on the king and caused Adda's transformation into a striga.
Cursed as a Striga
Adda was born a striga as a result of a curse cast by Ostrit, who was jealous of her mother's incestuous relationship with her father. Ostrit tried to put a curse on the king, which unintentionally resulted in her mother's death and her becoming a striga. For six years, Adda terrorized Vizima, killing its villagers. She was only cured after Triss Merigold sought out the help of renowned witcher Geralt of Rivia, who would need to keep her from her crypt until the morning.
On the night of her final full moon as a striga, she rose from her crypt. Geralt had tied Ostrit to the bed upstairs in the ruined palace and left him behind. Adda, as a fully transformed striga, killed him, and then attacked Geralt. He tried to entrap her with silver chains, but to no avail; the striga broke free. A fight ensued, which ultimately resulted in Adda being knocked unconscious. While she was down, Geralt placed a barrier over the entrance, some form of Yrden, preventing her from leaving. When she ran for the exit, the barrier knocked her back. Geralt then punched her while wearing brass knuckles. As the sun rose, both she and Geralt raced for the crypt. Geralt got to it first and sealed himself inside.
The sun was out, and Adda had almost fully transformed from a striga to a girl. Geralt slowly approached to examine her and ensure his efforts had been fruitful. She turned around and slashed his throat with her claws. Geralt bit her neck to get her off of him and then passed out.