Board Thread:Naruto Discussions/@comment-24514198-20140604211103/@comment-7862945-20140703185235

I just thought of something. If Kaguya really is the 10 tails, then is she really considered a new villain? She's just it's true form.

Then she isn't really a random character or anything. It's not unusual in a series to learn more about the final boss at the end or see them have a "true form" that looks completely different from what we expect.