The Rhenwars Saga is the story of a world where the forces of hell are worshiped by a quarter of the population and much of its countryside has been reduced to a Mordor-like hellhole. Opposing these forces are a bunch of magic-using sects and priesthoods who despise one another almost as much (if not more so) than the forces of hell. Despite its seeming Black And White Morality (see TV tropes) premise, it is actually a Gray and Gray Morality world where the so-called forces of evil are no arguably less dark than the fanatics opposing them.
In this case, the story takes place millennium later when humanity has rebuilt itself. A new order of mages now protects the world called the Sentinels and Darien Launchlin is preparing to join their ranks. Unfortunately, everything goes to hell as the Well of Tears (a gateway to said realm) is opened and the Sentinels wiped out save Darien himself. Darien, by the laws of magic, inherits the entirety of his order's power all at once. Not only will this eventually kill him but insanity is inevitable. Sort of like the Wheel of Time which I noticed several homages too and which has a few of the same themes.
Due to having lost his family and lover during the Sentinel's massacre, Darien has become suicidal and decides to bring the whole of his power against the forces of the Darklands. This terrifies all of the kingdoms who should, ostensibly, be his allies even as it gives him the power to potentially win the war outright. In this quest, he's also aided by Naia and Kyel who have their own reasons for wanting to break all convention.
I like Darien as a Rand al'Thor-esque hero. The fact he is working against a ticking clock which threatens to consume him at any time is one which is an intriguing premise. I'm a big fan of flawed antiheroes as any one who reads my writing can attest. I like the fact he longs for death to be united with his beloved, only to find out even that's impossible due to the fact her soul was consigned to the God of Darkness. He's not a particularly likable protagonist but none of the supporting cast give him much reason to be. All of them think of him as a ticking time bomb at best and none of them are allowing him to go through any sort of grieving process before throwing him at their enemies.
Strangely, one of the things I like best about this book is the "anti-romance" between Darien and Naia. I say anti-romance because it's really about deconstructing and battering down traditional fantasy romances. Darien is a dark and brooding figure heartbroken by the death/damnation of his lover. In a typical fantasy novel, Naia would help him heal his heart and we would root for them for a happily ever after. Not so here. M.L. Spencer shows how monumentally selfish Naia's feelings are as well as how completely uninterested in a relationship someone like Darien would be.
There's also a good amount of questioning whether Darien using the equivalent of magical weapons of mass destruction is actually a good thing. We support Darien in his quest for revenge and protect the, honestly, too stupid to live kingdoms of "good" but the methods he uses start at ruthless then rapidly move toward genocidal. The original Darkstorm novel questioned whether the "hero" was doing the right thing and Darkmage picks up with the consequences of his actions while this is much the same.
Darkmage is a book full of fantastic magical military action and lots of really bloody battle scenes. M.L Spencer has a gift for writing action scenes and moral ambiguity. I think fans of grimdark and more standard fantasy will enjoy this book. I also liked it enough to pick up the third book as soon as I finished this.