In the 'Meet the Authors' section of "Mistress of Ambiguities", the fourth book in the Silverglass series by J. F. Rivkin, we're told that 'J. F. Rivkin' is the shared pseudonym of two popular fantasy authors on opposite ends of the United States. Both of them collaborated on the first two Silverglass novels, while the second two, including "Witch of Rhostshyl", were penned by the "East Coast" J. F. Rivkin. Well, unfortunately it shows. The first two volumes in the series not only had well-drawn characters and tight dialogue, but lots of action and highly engaging supernatural plotlines that subverted (in a good way, not a destructive way) well-worn fantasy tropes such as elves and demons. "Rhostshyl" doesn't concern itself so much with epic fantasy, but rather with Nyctasia making the decision to return to her home city and set things to rights, preferably with Corson along to keep her in one piece.
This is a well-written and thoughtful novel, and it's great to see Corson and Nyc again, even if they spend over half the novel separated, with Corson in Chiastelm and Nyc still in the Midlands with her distant relatives. There's a ton of interaction with side-characters of varying degrees of likability. There are a few subplots, including an imprisoned ship-captain, an escaped slave and some acrobats, which basically go nowhere, and I could never quite see how they fit into the story, especially since the author had no problem passing over other long periods of time with simple narrative exposition. "Time passed and Nyc had arrived at such-and-such," etc. Maybe Rivkin is setting us up for events in Book 4.
However, "Witch of Rhostshyl" is an enjoyable read even without the influence of the West Coast J. F. Rivkin, and I decided not to ding the novel a star simply because it wasn't up to the standard set by the previous books. The "Silverglass" series is a highly enjoyable read and still exceeds modern day standards of epic fantasy storytelling, even if it's no longer exactly epic fantasy.