Geralt, Yennefer, and Ciri have all come into close contact with the King and his specters, either directly or through dreams.
Geralt was a member of the hunt for a time, after he gave the King his soul in exchange for Yennefer's. While he would escape eventually, he lost his memory in the process. In The Witcher 3: Wild Hunt, the Wild Hunt returns in an attempt to find and capture Ciri.