He was one of Yennefer's long-time lovers whom she had known for many years, often visiting and staying with him for several months. During one such occasion, when Yennefer travelled with Geralt to Aedd Gynvael, the two men learned of each other. Both Istredd and Geralt were unwilling to share Yennefer , with Istredd not caring if Yennefer had several non-serious lovers, but refused to share her with someone she was seriously in love with. During this time, he asked her to marry him and live together at his residence. Yennefer did not immediately give him an answer and became torn between picking Istredd or Geralt .
Istredd and Geralt then challenged each other to a duel to death for the right to exclusive access to Yennefer's affections (although they both knew whoever won would have to hide from her for some time until her rage ended). Both believed that Yennefer could not decide between them. However, Istredd, before going to fight Geralt , received a letter from an enchanted Kestrel sent by Yennefer telling him she had chosen to leave him. Istredd in grief, turned up to the fight bearing a sword instead of magic, hoping that Geralt would kill him.
Istredd proposed to Yennefer while she was with Geralt in Aedd Gynvael. He promised her stability, a home, a future, and the child(ren) she's longed for. However, Yennefer left the city even before Geralt, and Istredd ended up helping Geralt when he faced Dermot Marranga and his men.
Played by Bronisław Wrocławski.