Vortex is the 7th book in the Sten series, and it's a decent addition to the tale. It has all of the normal elements such as fantastic creatures and inescapable situations in a universe that only makes sense if you don't question it too hard. Like all the other books, it's best enjoyed as a "shut your brain off" joy ride.There are a couple differences from the other books. The first is that there tends to be a lot less action in this book. There's plenty of political intrigue and back-stabbing, but so few of the all-out battles that Sten normally fights through with his companions.The second difference is that while all the other books tend to stand on their own with a few flashbacks and the like, this book appears to exist almost entirely to set up the final installment. It's not necessarily a bad thing, but I just noticed it.
With the return of the Eternal Emperor, Sten enters service as diplomat plenipotentiary, trying to help keep the Empire together, even in the intrinsically fractious Altaic Cluster. But there's rottenness both in the Imperial chosen leaders and in the core of the Empire itself, putting Sten between a moral rock and a genocidal hard place.Good combo of SF military fantasy, guerrilla/revolutionary fiction, and continuing the narrative of what makes for an eternal empire ... and what can bring it down.