Spoiler
So I am a member of the companions, and I'm also a vampire (they are a good source of blood). I figured hey, since I'm a member I may as well do the questline. However, they want me to be a werewolf, and they are waiting for me in the underforge with an option " let us know when you are ready". I know I can stay a companion w/out being a werewolf, but can I continue the quest line without becoming one? It doesn't seem like I can...