Separatists. Grievous and his droids took out the nightsister warriors in the cartoon. So it becomes Dooku and Grievous vs Assajj and Talzin. Considering that Dooku beat Assajj pretty easily in the cartoon, it would then become Dooku and Grievous vs Talzin. I don't know the full extent of Talzin's power, but I don't think that she could take both of them.