Wizard King - Wyvern Master Chronicles, #4

Fiach is not a happy camper. There are far too many people wanting him dead. Add to that, dragon hunters now freely roam in three of the five kingdoms. And there's been another change of leadership at the College. Of course, that happened after the College was invaded by a neighboring kingdom. And there's more chilling news when he learns someone has discovered Lorcyn's sorcery and has turned a wyvern.
Brendal Pendragon, Lord of the Dragons, has come to him for help. It's now time to settle old scores and forever rid the world of dragon hunters. At the same time, he must defeat the marshalled forces of sorcery that threaten to return the world to those dark days when Lorcyn resurrected dead dragons and unleashed them to destroy his enemies. Fiach must choose. If he helps Brendal Pendragon, he could lose a kingdom.
If he stays in Wyndych, he could lose everything, the College included.