who or what was the stone wolf?

THe Great iron gates of the witches palace are open. Edmund focuses on his hatred for Peter to gain courage, and enters a courtyard, where he sees a lion and a dwarf. Slowly, he realizes that the creatures are made of stone, and that the courtyard is filled with similar statues....There is a stone wolf standing in the doorway, and he inches toward it, but it suddenly begins to talk. Edmund explains to the wolf who he is, and the wolf tells him to wait. Moments later, Fenris Ulf, the grey wolf and Chief of the White Witch's Secret Police, appears at the doorway and invites him in.