Legacy of Kings by C.S. Friedman

The conclusion to C.S. Friedman's Magister Trilogy.  (First book: Feast of Souls; second book: Wings of Wrath)

Legacy of Kings is an extremely satisfying climax to one of the most enjoyable fantasy series I've read.  Mysteries that are hinted at in the earlier books become clear in Legacy of Kings, and certain characters reach their full and ridiculously awesome potential!