Free Will

The most important theme of Cold Days is the concept of Free Will. Dresden cannot escape the mantle of the Winter Knight, because its presence keeps him alive. And yet, he has to fight against the dark impulses it brings up in him. If he were a less moral person, less devoutly committed to his personal code of ethics, he could embrace that darkness and do as he wishes. But he is Harry Blackstone Copperfield Dresden, and he isn't going to walk away from all that he has built inside himself.

The Will of a wizard is a strongly developed thing, but it is not necessarily a match for the mantle of the Winter Knight. His predecessor might not have started out an evil man, but he certainly became evil in the end, abusing everyone who got in his way. Dresden takes this example as fair warning...