Dragons of Argonath — Christopher Rowley

A SORCEROR'S REIGN OF CHAOS
Battle-scarred and weary, the mighty Bazil Broketail and dragoneer Relkin return home to cheering crowds, great feasts, and raging bonfires. But now, out of the mists and across the green valleys of their native land comes the savage clamor of war, pitting Bazil and Relkin against an enemy more terrifying than any they have confronted before.

A BATTLEDRAGON'S LAST STAND
The Dominator, crusher of worlds, has risen to sow royal intrigue and rebellion within the Empire of the Rose--a diabolical scheme that could destroy armies of men and battledragons alike. In this realm of treachery and bloodlust, Bazil and Relkin's beloved Empire teeters on the brink of annihilation. And as he raises his sword in defense of freedom, Relkin realizes that the only way to destroy the Dominator is to draw on his own untested--and frightening--powers of magic...A magic he might not be able to control.