I wonder if Ruby is a villain? She seemed to take pleasure in making that Deadite suffer. Ash would have killed it as quick as he could. She wants the book. But why does she want it?
I can't remember if they've revealed Ruby's last name in the show yet, but on press releases and imdb, her name is...
...Knowby, like the Professor from the first movie and his daughter in who was killed in the second movie. She probably wants the book because of all that it's taken away from her family. After all, Prof. Knowby is the one who started this whole thing in the first place.
It's pretty neat that she seems to have the Kandarian Dagger from the first two movies, too.