As confirmed above, it was definitely Ford. That was one of the many layers to this brilliant episode. A constant theme in Buffy (and Angel as well) is the inherently grey nature of the demon-hunting business, and it is never addressed more eloquently than in this episode. This is metaphor, of course. What we're really talking about is the life-living biz.
Giles: Yes, it's terribly simple. The good guys are always stalwart and true, the bad guys are easily distinguished by their pointy horns or black hats, and, uh, we always defeat them and save the day. No one ever dies, and everybody lives happily ever after
Buffy: Liar.