[quote=@Ruby]
Question, because I can see pros and cons to both aspects of it, how familiar (if at all) should the Scoobies be with Mr. Pierce?

Know he's the school librarian? 

Know he's a Watcher? 

Should he already be helping them out a little?

Should he already be guiding them in their self-proclaimed fight?

Want everyone's opinion, if you have one. 
[/quote]

It would probably make most logical sense if he was just an unusually helpful librarian, always there to guide them in the right direction, but without telling them any more than they needed to know. Logic is only one consideration though, not necessarily the most important thing. 

So I guess it depends on whether we'd be going for a quick start where everyone is on the same page and very little needs to be explained or set up, or spending some time in-character explaining it to the group and dealing with their reactions to it. I think I prefer the second scenario a little, but honestly I'm cool with whatever xD