Cassie

"Cassie" is (apparently) the name of a rag doll that was found in the mausoleum of Anet Harr. While the Breakfast Club was investigating the deaths of the Black Mug Brotherhood

they discovered the doll and that it appeared to move when it is not being watched to point in a specific direction -- but there was no indication of why the doll was pointing in that specific direction.

Later, the Club followed this pointer through the Nightwood, and Cassie led them to the Wreck of the Pride of Stormhome.