After watching The Clone Wars for a couple of seasons, and knowing the influence that George has on the show, I think it has become clear that a villain does not necessarily have to be a Sith to be a good one. Here are a couple of possibilities of who could be the next Star Wars villain:
1. The Nightsisters
When we went into the backstory of Asajj Ventress, we discovered that she originally came from a clan of Witches from the planet Dathomir, known as Nightsisters. This clan of witches was known for being practitioners of the dark side of the force, and had used the force differently from what we saw in both the Jedi and the Sith. The Nightsisters in particular, as seen in the show, aren't that powerful to be honest. General Grievous managed to kill almost all of the members save for Mother Talzin (below) the head of the clan. She clearly is far more powerful than the other Nightsisters, and has the kind of mystery that made the character of Darth Sidious so great. It's difficult to see if she will reorganize the clan to make them far more powerful and pave way to Episode VII, so for that we will have to tune in to the show to get some answers.
This concept also taken from The Clone Wars, offers a very different insight to Star Wars, than anything we have seen before in the past. As we saw them in the Mortis trilogy, the so called force wielders were a group of beings that could manipulate the Force like no other being. The Daughter was the representation of the light side, the Son (below) of the dark, and the Father mantained the balance. Their is still a lot of mystery regarding what exactly happened in this series of episodes, and it remains even more mysterious when you counteract with the possibility of another Force-wielder making its way into the movie. For that, we will have to wait and see.
3. A Lightsaber wielding cyborg
Obviously, for this one to work, the General Grievous type cyborg would have to be a sidekick to the real villain, much to how Grievous was in Episode III. Though he might be too much like Grievous if he can't use the Force.
4. Former Jedi turned to the Dark Side
Similar too how Pong Krell served as a ''Dark'' Jedi in the Umbara arc back in Season 4, so could one of the villains be a former student to Luke who turned to the dark side. Again, he probably would have to as a sidekick villain.
5. The Unknown Factor
A Star Wars movie without the Sith will not mean that their won't be lightsaber fights, nor that it won't be a good movie. I highly doubt that Lucas will overrun what he himself established in the movies, so it's likely that some sect of the dark side of the Force will be the next villain. So, the most likely contender, unless Lucas and the writers make one up from scratch, will be the Nightsisters, and possibly a force-wielder interacting. What do you guys think?
Share your thoughts below.