I knew about the 4th and 5th before I went to see part 3.
These movies are absolutly great because they break all the rules of the imortal bad guy. The twist these movies have gives the audiance a total bitchslap just when they think they know the ending. And instead of weaving a story that extends, the writers weave the new story intricatly back into the old. But I won't ruin it for those of you who have yet to see part 3.