Elvenborn. The Halfblood Chronicles, #3

From Grand Masters Mercedes Lackey and Andre Norton - Book Three of the legendary Halfblood Chronicles. The Elvenbane has awakened more than halfblood magic. Across the elven lands, rebellion spreads: young lords defy their fathers, human slaves slip their chains, and the immortal Great Lords face a threat they can no longer dismiss as rumor or prophecy. Kyrtian V'dyll Lord Prastaran has always been considered an eccentric.
While other elven lords indulge in court intrigue and cruelty, Kyrtian studies military tactics, trains his human "slaves" as soldiers, and rules an estate where loyalty is earned rather than forced by magic. His enemies call him ridiculous, provincial, and unfit to rule. They are about to learn how dangerous an underestimated man can be. When the Great Lords need a commander capable of crushing the Young Lords' Rebellion, Kyrtian's strange obsession with strategy becomes his greatest weapon-and his greatest peril.
If he succeeds, he may be ordered next against Shana, the Elvenbane, and the hidden stronghold of the halfblood wizards and dragons. If he refuses, he risks his estate, his people, and his life. But Kyrtian is not the only one playing a dangerous game. Ambitious rivals move to destroy him, the Council hungers for control, and the rebels, wizards, dragons, and humans must decide whether an elven lord can ever truly be trusted.
Before the old order falls, enemies will have to become allies-and one lord born to privilege must choose between the world that made him and the people who may be its only hope. An epic of dragon magic, military strategy, slave rebellion, court intrigue, and impossible alliances, in the tradition of Anne McCaffrey's Pern. Elvenborn continues the saga begun in Elvenbane and Elvenblood - newly revised and illustrated, and complete at last with the long-awaited finale.