The other three PCs aside, I just want to address the two Force users in my game. It's time they face a dark side user, but I don't want to accidentally make him too powerful.
The two PCs have grown pretty powerful compared to the sort of foes the group has faced so far. They've got many sessions and lots of XPs under them. One is a Mystic (Seer) with Influence , Move , and Seek . The other is a Guardian (Armorer) with Bind and Sense . Neither have a proper lightsaber yet. The Guardian has a training lightsaber.
Dark forces have taken a notice to these two and they're sending an acolyte to kill them. Of course, I don't want to unintentionally create an NPC that's too much for them to handle and they actually get killed. I want a challenging fight that makes the two players realize they're taking their first steps into a larger world now. The acolyte will strike when the other PCs can't help their comrades. If need be, he'll send other others to attack them at the same time the Force-users are getting attacked.
I do want this dark acolyte assailant to be more of a physical character. He's going to fight them with a corrupted-crystal-lightsaber. (Corrupted crystals are in Disciples of Harmony .) However, I also want him to have a Force power or two up his sleeve as well.
I am very open to suggestions. Species, lightsaber form, Force powers, talents... I think a non-human would be more cool than a human for this NPC. I do know what I don't want for a species: not a Twi'lek, not a Rodian, not a Togruta, not a Shistavanen, not a Trandoshan, not a Karkarodon, and not a Kyuzo. They have encountered all of these in recent sessions.
Whacha got!