While he seems similar to the familiars created by Midchildan mages, Zafira insists that he is a "Guard Beast". Whether that is a semantic difference (similar to the practice of calling Ancient Belkan mages as "Knights") or a more fundamental difference is unknown. It is possible that as a servant of the Book of Darkness, Zafira is unique as the only Guard Beast. In addition to that (or perhaps because of it), he is treated as an equal by the other Wolkenritter despite being the only one who is not a Knight, and like them he responds to Hayate alone as his mistress.