The last dragonlord - Joanne Bertin

For centuries the Dragonlords - humans who can sorcerously become dragons at will - have aided true humans, and sat in judgement on their wars and political wranglings. Now Linden Rathan, youngest of the Lords and still awaiting his soultwin after six hundred years, is sent to Casna in the land of Cassori to judge a regency dispute, together with two of his fellow Dragonlords.
But behind the dispute is a dark magic set to destroy Linden and all the Dragonlords. Just as he believes he has found his true love, Linden must undertake the protection of both himself and his entire race.