I would really like to write a review that discussed some of the more interesting aspects of the narrative, how they complement and sustain the underlying themes, but that would mean assuming that readers of the review had already read the book and would end up giving away part of the plot, so I'll restrain myself. This isn't the right venue for that sort of reviewing. However, The Demon's Lexicon is a story that can sustain all sorts of interesting discussion: teachers, take note!
The Demon's Lexicon takes place in contemporary England, our own world with an underlayer of magic that few know anything about. Brothers Alan and Nick Ryves, with their insane mother Olivia, are deeply involved in that underworld. For almost as long as Nick can remember, they have been hunted by magicians attempting to reclaim something stolen from them by Olivia. Magicians, in this reality, gain most of their power by controlling demons, who hunger for the life and warmth of this world. This demands the sacrifice of human lives. Years before, their father died and Alan was crippled escaping a magician's trap. Both have become consummate warriors, highly knowledgeable in the ways of magicians and demons while never stepping over into magician's evil themselves. While Nick's life is focused on his brother (a focus that intensifies almost to obsession as the story progresses), Alan tries not only to look after his younger brother and Olivia, but to help Mae and Jamie, siblings who come to the brothers for help after Jamie is seduced and marked by a demon. Three demon's marks means demonic possession and rapid death; Jamie has two. Alan's actions put his own life at risk, to Nick's fury. The foursome end up going from hunted to hunters, attempting to kill members of the magicians' circle controlling the demon in order to save Alan and Jamie. Nick discovers lie upon lie in his family's past, though, and realizes that even Alan is lying to him about a number of crucial things.
Brennan's closely-focused third-person narrative tells the story from Nick's perspective, which helps to tie the reader's sympathy to someone who, viewed from outside, could be very unsympathetic in his arrogance and coldness to anyone other than his brother. As the younger sibling and the person who knows least about the past, too, Nick's is the ideal point of view for intensifying the mystery. His ongoing struggle to restrain his worst impulses and live up to his brother's expectations is where his real heroism emerges, not in his skill with sword and knife. The true hero, though, is Alan, a scholar and fighter who has given up much to look after this troubled family. He often appears to allow himself to be overshadowed by Nick, who is menacing, sexy, volatile and definitely the one you'd notice first -- a mistake more than one villain makes. Alan's integrity, loyalty, and ongoing sacrifice of his own desires for others is the force that ultimately shapes the story.
Brennan's action scenes are thrilling. The sometimes violent and bitter quarrels and the deep affection between the brothers all contribute to the satisfying depth of the story. She is also a writer who weaves in a lot of humour, not only in Jamie's defensive wise-cracking and the brothers' banter, but in the juxtaposition of the unexpected and the everyday, the sword stored under the kitchen sink, the difficulty of a corpse in the kitchen when a girl you fancy shows up at the door. The Demon's Lexicon is well worth reading, hard to put down once begun; I'm looking forward eagerly to Brennan's next book.