This is slightly off topic but we all know that Fredon Nadd's spirit was destroyed by Exar Kun right? Well then what was the point of Nihilus's sith going to his tomb? Were they trying to bring back the Ancient Sith Lord back to life or prepare more power that Nihilus could consume or what?
The Sith were preparing a dark ritual to take control of all of the beasts on Onderon. This would have led to the defeat of Queen Talia and the fall of Iziz.