Will The Master be the main villain of the show?

One of the things that Joss pointed out was that one of the downsides of the Master story was that he never got out, and because he never got out, there wasn't actually much mayhem that he could cause. So, why not focus on other activities that went on at that time?

There will certainly be mentions of that sort of thing within the continuity, but you don't need to know the story of the Master to figure out what's going on. They still live on the Hellmouth, so there are plenty of other ghoulies to play and fight with. We have talked about the idea of creating what we refer to as our 'arch nemesis' who would be a recurring villain that was unique to the animated series, but so far I can't actually comment on that part.

We've also heard stories that Dawn may be retroactively added to the stories, as everyone remembers being around. Is this true?

There will be some surprises, that's all we can say.