A Dragon at World's End — Christopher Rowley

LAND OF TERROR
Surviving a volcano's blast and separated from the 109th Marneri Dragons, the extraordinary Bazil Broketail and dragoneer Relkin find themselves in a vast, untamed jungle that stretches south from the shores of the Inland Sea. Prowled by giant beasts and carnivorous lizards, its innumerable dangers are legendary. Bazil and Relkin would like nothing more than to rejoin their unit--but fate has intervened. The Ardu, the mysterious forest folk of this savage region, are in desperate need of help in their struggle against the evil slavers who prey upon them. So the battledragon and his boy become champions in the fight for freedom.

CITY OF SORCERY
But Relkin is abducted by slavers and taken south to be sold. There, in the city of Mirchaz, where Elven wizard-lords hold court over a population in chains, Relkin finds himself a pawn in a cruel game of magical manipulation. And while he struggles to free himself by developing his own limited powers of magic, his friend Bazil prepares a bold assault on Mirchaz itself that could get them both killed....