This book removes the "safety net" of fantasy which we've all become accustomed to existing. Specifically, the one which implies that not only are the heroes good but their decisions are the right ones. M.L. Spencer may not have any moments as shocking as George R.R. Martin's treatment of Ned Stark or the Red Wedding but she certainly has twisted the typical narrative into knots.
The premise is there is a magical cataclysm coming to the world. Every 1000 years or so, magic upends itself and kills everyone who practices it as well as destroys all creations with magic. The disaster is so complete, no one really leaves any records about it either. This time, however, the leadership of the mage community has come up with a solution that is controversial to say the least. Harnessing the power of Hell (yes, I said hell), they are going to stop the cataclysm in its tracks. It only requires them adding the God of Evil to the deities which are worshiped on their world. Yeah, there's no way this plan could go wrong.
Ironically, though, I had bigger recriminations for the book's ostensible hero. Branden intends to stop the "evil" conspiracy no matter what. He would be a stereotypical hero if not for the fact Branden has no plan to stop the cataclysm and self-righteously is willing to condemn countless innocents to death as well as let an entire culture die in order to avoid Hell's power from being used. In that respect, it's very easy to see one or the other "side" in this conflict as the hero and the other as the villain.
The other major protagonists are Meriss and Quin. Meriss is a deconstruction of the typical plucky young heroines in Young Adult fiction as she starts out as idealistic and a rule-breaker but quickly loses the former while the later destroys her career. No Dumbledore to protect her from the consequences of her actions. She also falls for the "bad boy" Quin, who is a incredibly beautiful amoral mage with a tragic past. All of these qualities more or less setting her up for a romance that is more likely to blow up in her face than succeed. Quin being Branden's brother is there to provide a good bit of commentary on why fighting for "glorious justice" isn't exactly a good thing.
Darkstorm has an enjoyable fast pace which manages to tell an epic story about the protagonists in a single novel. I, honestly, think that's a bit to the book's deterrent as the story would have benefited from being stretched out to three novels. Branden never gets to confront the consequences of his choices, Meriss and Quin's romance is insufficiently resolved, plus the conclusion is left ambiguous. There are sequels to the story with Darkmage and Darklands but those are set millennium later.
Despite the fact I think the book is a little too small for its subject matter, I will say the author manages to avoid underscribing things as well. The world has just enough detail that I knew what every faction was after, what the relationships between countries was, and how one action was likely to affect our heroes' chances. There a lot of story packed in 304 pages and that's a skill which few authors possess. Even so, I can't help but think it was too much story for one novel. I felt similarly about Richard Knaak's The Legend of Huma, which this book somewhat reminded me of.
In conclusion, I recommend Darkstorm as an excellent short epic fantasy read and I have since picked up the subsequent volumes in the series. The book isn't one which reinvents the fantasy wheel but I found it entertaining, the characters likable, and the world-building consistent. I'd classify it as dark fantasy over grimdark but the line has always been blurry between the two for me. It's also lacking in the visceral grit, violence, and swearing which is typically found in the latter. You could easily put this in the Young Adult section alongside the Throne of Glass or older Dungeons and Dragons books.