system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Wars] So the jedi have 7 types of lightsaber combat. Do the Sith have any equivalent forms of combat? Or do they use their own forms?
gpt
There are actually more than just 7 forms. There is the Vapaad variation on Juyo, Jar'Kai and forms dedicated to specific weapons, the saberstaff, saberpike, and lightwhip.

I'd assume we can infer from this that there would also be a dedicated form for crossguard lightsabers.

But the answer is no.

Consider that the Sith Order is a organisation that stems from the Jedi Order as it is. Their combat teachings are the Jedi teaching. The evolution of forms happened to counter the threats as they arose in the Galaxy. The Sith faced the same challenges.

What's more probable is that the Nighsisters of Dathomir likely have their own forms of combat that are ancient and specific to them.