The ancient dragon Valdearg was briefly introduced in T.A. Barron's "Seven Songs of Merlin." So guess what the antagonist of "The Fires of Merlin" is!
The third volume of this Arthurian fantasy epic introduces some nasty new beasties, magical threats and some explosive dragon action. Barron seems to have overcome his initial roughness, and allows the plot to flow as smoothly as his nature-based writing, as well as the introduction of some interesting new characters.
After barely saving his mother's life, Emrys Merlin is relaxing with his family... only to have their peace destroyed when a monstrous magic-sucking monster called a kreelix appears. They were supposedly extinct, but have somehow reappeared -- and to make matters worse, Valdearg (aka "Wings of Fire") has awakened from his slumber, and is on the warpath for whoever killed his hatchlings.
The problem is that there is a prophecy that Wings of Fire's clash with his old enemy (presumed to be a wizard) will result in both of them dying. So Merlin sets out to discover what is happening on "Fincayra's darkest day," and finds himself enmeshed with strange sorceresses, a magical conspiracy, a pair of deer-people, and eventually with the ancient dragon himself...
"The Fires of Merlin" sets aside the foresty Celtic symbolism of the previous two books, in favor of fire -- harps burn, lava burns, dragons blast fire, and homicidal anger rages out of control. He also seems to have exhausted his mythological store for the moment, because most of the magical goings-on in this book are pretty original creations.
Barron's writing sometimes gets a bit overlush, but it's loaded down with haunting, detailed moments (the deer-people's transformations), eerie threats, and the occasional moment of comic relief (the baby dragon). But the story is overall very grim, particularly since this is the first of Merlin's stories in which his death seems to be assured. Whether or not he will actually die, there's a dark cloud hanging over everything he does.
The biggest problem is perhaps the kreelixes -- they're an interesting idea, but they sound more like something out of Star Trek than Arthurian legend. I'm just saying.
Merlin is a little older and wiser in this one, and he seems to be feeling the first stirrings of romantic feelings for the bland deer-woman Hallia. And Valdearg is a wonderful antagonist -- he'a an aggressive killer, but he's not evil and at times he even shows signs of dignity and endearing sentiment.
"The Fires of Merlin" temporarily ditches the Celtic myth'n'legend, in favor of dragons and a few new inventions of the author's. A solid, richly-written fantasy.