Billy_Blood
Potential
Ok, so the title was kind of a lie, since I have no real theory. but I do have a few guesses. Keep in mind I have yet to see Showtime, so I don't know eveything.
When Spike still had the chip, he was able to fight Buffy without activiting the chip. The chip give him a shock everytime he hurt a human, but it had no affect if he killed demons. Spike thought it was because when Buffy came back from the grave, something went wrong. The First is here becuase Buffy was resurrected. And we found out the first slayer's powers came from being part demon, the same powers those shaman guys offered Buffy to defeat the First Evil. This is all probably intertwined with one another, and may possible have something to do with the finale.
When Spike still had the chip, he was able to fight Buffy without activiting the chip. The chip give him a shock everytime he hurt a human, but it had no affect if he killed demons. Spike thought it was because when Buffy came back from the grave, something went wrong. The First is here becuase Buffy was resurrected. And we found out the first slayer's powers came from being part demon, the same powers those shaman guys offered Buffy to defeat the First Evil. This is all probably intertwined with one another, and may possible have something to do with the finale.