David Mack's most likely talking about the posters here and the upcoming books named 'Fall'.
As for the 'Fall' books - as per the spoilers in this thread:
-they start with ~there was so much blood;
-during the brainstorming sessions, there appeared comments like ~they are getting pretty grim.
The tone of the books - new battlestar galactica-ish - is obvious.
High body count; whether it's the federation, romulans or whatever, you can be sure it will survive to feature in the next book.