I recently read the Christmas Eve short story, after rereading the whole of the series.
One thing stands out to me, the lack of Karrin Murphy in the Christmas Eve story. Harry and her began a new relationship in Skin Game, they kissed, they were now "an item"
She's not there with Harry on Christmas Eve, this strikes me as odd. I have a theory, and it's not her being one of the dead.
I have always felt that her story echoes Harry's. Things happen to Harry and similar things happen to her later on. Both lose swords of the cross, both get injured and will never be the same physically again etc.
I wonder, and this is my theory, that among the many funerals that Molly paid for, was a funeral for Fix, that he dies and that the mantel of Summer Knight ends up on Karrin Murphy.
That just as Harry and Karrin get together, something else happens to keep them apart. That it would never be allowed for the Knights of Summer and Winter to be intimate. This of course would give Harry an extra push to find a way to rid himself of the mantle, which, as stated by Odin in Cold Days, "Many, many mantles are worn — or discarded — on Halloween night, wizard."
Any thoughts?