Speaking of what a weird-ass pervert Strahd is, it turns out he likes to be the creamy filling in a big necromantic Oreo. You see, Soth has been injured fighting a dragon so Strahd offers to act as a conduit that transfers life force from some mortal mook to the deathknight. And make no mistake, Strahd likes being the monkey in the middle: “The look on Strahd's face told Soth that the vampire enjoyed the workings of this particular spell. Strahd's dark eyes rolled back and fluttered, showing only their whites. His pale cheeks flushed with color; his cruel mouth stretched into a wide smile of pleasure. The vampire's fangs had extended to their full length.” Extended, to their full length, no less.
At this point in the novel it is painfully clear what Lowder's biggest problem is with the narrative: everything that is happening is just him killing time (and page count) on the way to giving Soth his own domain in Ravenloft. Soth and his werebadger (!!!) pal go to Gundarak on a quest to use a supposed portal out of Ravenloft that amounts to nothing; Magda, the only character we can identify with because she's the only one with a reasonable worldview and graspable goals, buggers off in the middle of the night—never to reappear—because Lowder clearly just doesn't have a plot arc in mind for her. All of this is ultimately meaningless and the novel is really just running down the shot clock before it throws Soth into Sithicus.
Somewhat entertainingly, Soth uses a Bigby's Hand spell at the climax. I mean, come on, that joke just makes itself.
Ultimately, Soth's reoccurring problem is that he can see that he's walking into traps, but he's so dumb he blunders in anyway. This happens in Soth's back-story when he knows he's being tricked into leaving his quest to spare Krynn from the Cataclysm, and it happens again at the end of Knight of the Black Rose when Strahd walks Soth into the mists so that a new domain will form around him. The thing is, Strahd doesn't exactly have to get Machiavellian to maneuver Soth out of Barovia. Essentially, Soth says, “You're trying to trick me into entering the mists!” Strahd says, “Yep, I am.” Soth says, “Okay, see you later! Imma go into the mists now.” Soth is so hammer-headed that it is a wonder that Jander doesn't show up to put the moves on him.
I have to give Lowder credit, though, Knight of the Black Rose at least ends on a note that at least recycles some conventions found in Gothic literature. Nedargaard Keep is described as the unheimlich double of Soth's fortress in Krynn; it's almost like he castle he's familiar with, but the details are off just enough to drive him mad. Still, this bit is too little too late. Here's the Cliff Notes for the novel: “Strahd goes to Ravenloft, Strahd continues to perv, Soth gets stuck in Sithicus.” And that's all there is.