Haha that I can actually picture happening. Because I can't see anyone in their right mind walking down to a demon willingly haha. 

What kind of brand are you thinking about? Like a brand on the skin/fur or like a necklace/collar type thing? I like the idea of it being the first shift being the final part of the ceremony! You could say that the demon is the cause of the first shift in that case, seeing that the curse has been in their bloodline.