Ulfhedinn ... have you met? (The Witcher 3: Wild Hunt)

I think many in the bestiary have come across the kind of damned "ulfheedin". But during the passage of the game, this monster did not meet. Hence the question for the community: are there any tasks related to the ulfhedin or its subspecies - voref? where and when exactly can you find such a miracle? how many play I meet some wolves.

PS I apologize if a similar topic has been created somewhere on the forum, it's just very difficult to check them all. In the wiki of this game, no more is said about the specified monster than in the bestiary of the game.