While i don't completely understand everything Kash said (it's 4am) I'm not a big fan of linking two BB together. I think every season should stand alone. It just seems to over-complicate it.
This would just be a way to logically explain how its all connected, and give us a chance to go full circle and tie up all loose ends.
Here is a summary of what Kash said.
We have 1)Aurellius the Slayer (in Roman times)
She is then vamped and becomes 2) Aurellius the Vampire
Her soul is then cast into hell when she became a vampire. Renegade Watcher's felt it was unfair for her soul to be sent to torment, thus fled the Council and guarded over her soul. Her soul, while in hell, then became known as the 3)Purseplexa (sp). Those renegade watcher's evolved into the group that was mentioned in S6 that tried to bring Purseplexa back, and remember, the temple Willow tried to raise in s6 was the link to Perseplexa. Now, Aurellius the vampire is trying to free her soul (known as Prosoplexa (sp)) and has traveled to Sunnydale to do see. Aurellius calls on the powers of the 4 horsemen to do this, not knowing what her soul (Proseplexa) is actually planning on doing...which in fact is incenerating the Earth...like revenge.
