The Phoenix Transformed by Mercedes Lackey and James Mallory

They were too late. When Tiercel Rolfort and Harrier Gillain left the city of Armethalieh to see what was causing Tyr's nightmares and hopefully cure it, they discovered that they were meant to travel south and prevent the return of a great evil to the world. Bisochim, a WildMage of the Isavieni people, had been in contact with an otherworldly evil that played him masterfully, convincing him that true balance meant returning the Spirit of Darkness to the land and imprisoning it in a human body.

But they are too late, and Bisochim discovers, also too late, that the Spirit, a female of the Otherworld named Ahairan, has been given bodily form by Bisochim. But far from being "Imprisoned" by such a form, it frees her to do more evil in the world, and to bring through the rest of her people and create a hell on earth.

Though they were too late, Tyr and Harrier realize that they still must fight against Ahairan, and save the Isavieni people. Tyr, for his part, feels bereft. Ancaladar, his Dragon bonded, has gone and will never return. And without the bond that allowed him to do High Magic, he feels both bereft and useless- wondering why he is still around when he can't help the situation one bit. Also, with Ancaladar gone, his bulwark against the nightmares that troubled him is gone, and he returns to being short on sleep.

Harrier, for his own part, is a Knight-Mage, but he feels that his abilities are merely delaying the inevitable rather than actually helping destroy Ahairan. After discovering that Bisochim has a bonded dragon of his own, he won't let Bisochim seek atonement in suicide, but coerces the Wildmage into helping save the people who his blindness and foolishness nearly destroyed. But when Ahairan uses the bodies of their own dead against them, Harrier has to adapt to her tactics, and force the Isavieni to overturn many generations of their own traditions to be able to survive what Ahairan is throwing at them.

And when they rescue a delegation from Armethalieh, with them is Harrier's brother Eugens, who has been looking for the two of them when they disappeared with no word for a year. He wants Harrier to return to Armethalieh with him and just let the whole situation resolve itself on its own. But Harrier knows that simply isn't going to happen, and the remnants of the delegation only seem to cause trouble for him.

Even Shaiara has problems dealing with the people who believe she and her tribe abandoned them, and with her people's unwillingness to give up what they have always known to follow the new ways that Harrier is pushing on them to survive. But will Harrier's Knight Mage duties pull him away from her, and away from the desert? Will he desert his duties to return to Armethalieh, and his old life that he has always wanted to regain?

A fitting end for this series, with plenty of battles, but the drama isn't in the battles, it's in the slow, hard slog of moving the Isavieni out of the way of danger. Unfortunately, there is no real place out of danger, and Ahairan makes very sure of that, sending mutated creatures of the desert at the Isavieni, along with legions upon legions of the dead- both the Isavieni dead, and the many casualties of the war they prosecuted in the Iteru cities.

It becomes a slow, deadly war of attrition that is compelling in its own way, and the only man who can help keep the tribes alive is Bisochim, the man who is responsible for bringing Ahairan into the world and providing her with a body to do evil with. It was surprising that Bisochim's "beloved" was his bonded Dragon, Saravasse, who he thought he was doing everything for. In the end, there is quite a surprise with how this turns out, and i won't spoil it by giving it away. Suffice to say that I never expected it.

I liked this book much better than the ones who came before it, but I scarcely found any of the protagonists truly compelling. I had wanted to see another book after the first Knight-Mage Trilogy, but this one was scarcely the one I'd been expecting. But it didn't thrill me like the first one did, and I didn't find any of the characters as compelling as Idalia, Kellen and the rest. Yeah, it was a sequel, but you could pass it by and not really miss anything of what happened. I found it rather... disappointing.. I wouldn't recommend it, but YMMV, as always