I suppose I ought to have a sort of summary, since none of the snippets take place at the beginning.
Rafe: main character. Brilliant, deeply awkward engineer. Moderately asexual (as all good main characters are). He was once hired (under duress) to build killer robot soldiers, which he handled without too much moral difficulty. Later stole his robots back, reprogrammed them, and let them loose on the population to help counter the zombie plague. These wayward androids are usually called Angels by the general population.
Hollis: has boundary issues. Orphaned at a young age by the epidemic and then passed among various horrifying situations. Met Rafe as a guard while he was building the robots and developed a rather unhealthy attachment. Towards the end of the story, Hollis and Rafe have developed a sort of mild telepathy. His life seems to revolve around Rafe, in much the same way as the chain revolves around a chainsaw.
Flora & Michael: Rafe's close friends, a married couple, and quite possibly the only people Rafe has ever attempted to have any sort of sexual relationship with. They aren't aware that the Angels are androids (to be fair, Rafe and Hollis are the only ones who know) or that Rafe built them, although they do know that there is some odd connection between Rafe, Hollis, and the Angels. They are both deeply mistrustful of Hollis in particular, which Flora can be rather vocal about.
Snippets to follow.