I am hoping one of the developers can chime in on this with their interpretation or intentions.
In the core game they talk about the nature of undeath a little bit. Mostly in that it naturally occurs for the most part. Undead just kind rise up and go about their business until sure time as they find their peace and rest.
The Bitter Reach however does not really go into the death rituals in the new area. Probably due to page count and such. Cool. It makes sense that you need to be really particular about what you add to a book like that. Is undeath the same there? Is it the same everywhere else? Is undeath in the Raven Lands a historical issue or is it a issue that came about after the bloodmist? Is naturally occurring undeath increased by these events?
Basically... what is the nature of natural undeath? And how does it impact the different races? Does it occur mostly with humans? Elves wouldn't have undead since their bodies are more a construct than anything else. What about dwarves? Orcs? Halflings and Goblins? Wolfkin?