How does the author address the theme of separation in the novel, The Hounds of God?

The novel is full of anguished separations. At its opening, Thea and their newborn twins are magically whisked away from Alf. At its ending, Nikki and Jehan lose their friend Alf forever as the magic mist closes off the elven realm. In between, other events tear people apart. The theme of separation ties into the series' premise of elven semi-immortality. Separation and loss are part of what it means to be human.