There was a little talk that in the Space Wolves most dire need, Bjorn the Fellhanded would not awake from his slumber to aid in the defense of Fenris. Well, here is why.
Spoilers below the fold.
Warning, Do not read if you do not want to know this before hand you read the book
Bjorn the Fellhanded apparently is incredibly psychic, and is battling the Daemons from within the warp. Bjorn is a big favorite among many Space Wolf fans.
The truth about Bjorn's Slumber...... in a single pic
For more information on who Bjorn the Fellhanded is