Big Brain Ideas
A lot of the World Axis cosmology was written up before the Revenants, Shades, and Vyrolka were written up. The Shadar-kai were in the Monster Manual and the Vistani were written up fairly early in Dragon Magazine, so I imagine that those were the only "Shadow races" thought to be included in the Shadowfell.I agree that revenants and shades are cool. Of course there are also races like vryloka and vistani. Of all these races, I believe that only Vistani get any mention at all in this book! That's a bit odd. I can see publishing schedules preventing the inclusion of vryloka, who came out in Heroes of Shadow, released immediately before this boxed set, but revenants had been around for a while so it is surprising that there is almost no mention of them (or if there is, I don't recall it - maybe we'll be surprised later).