SHADOWBORN

Final installment of Sinclair's romantic daylight vs. darkness fantasy trilogy, following Lightborn (2010). 

Hundreds of years ago a war between powerful mages resulted in the world being sundered in twain. The Lightborn require light to survive and are killed by darkness, while for the sightless Darkborn—they have a sort of blindsight called "sonn"—the reverse is true. Over time the two peoples made an uneasy accommodation, but now both face slavery or annihilation by the mysterious Shadowborn, whose magic is more powerful than either and whose motives, initially at least, remain unknown. Sociologically, society resembles the English Regency with its frilly entitlements and deference to the aristocracy, while technologically it's more late Victorian, with railways, modern weaponry and scientific experimentation. Another complication is that the haughty Lightborn mages, for all their organization, can't detect the Shadowborn or their magic, so when the Shadowborn assault the Darkborn stronghold of  Stranhorne, the Lightborn Prince Fejelis immediately blames the Darkborn. Leading the Darkborn defenders is Ishmael, a mage no longer able to exercise his magic, and his physician friend Balthasar Hearne, who believes that his wife, the powerful but untrained mage Lady Telmaine, is dead, executed by the Lightborn. What nobody yet grasps is that the Shadowborn mages can not only ensorcel large groups of people, but they can take the semblance of others. However, the huge cast, each with his or her style, title and particular magic talent or lack thereof, and complex web of interactions, accusations and suspicions, makes this volume a tough place to start for newcomers.

Conceptually satisfying and thoroughly absorbing, if overpopulated and sometimes overwhelming.