This looked so interesting I went way back and started from the first story a couple chapters ago and just caught up to this chapter. Hope that made sense. Anyway, great stories and I've had a grand time reading them so far! Only problem is now I have to wait for the next chapter instead of just clicking a next link. Heh.
The relationship between the two is great and I like how you've set Spike up as Master of the Hellmouth. You've presented Spike and Xander as complex characters, but you've also brought a depth to characters like Tony and Anya that are often left as something like cardboard caricatures of the bad father and the bitchy ex.