Fae hound

Fae hounds are similar to the Black Dogs of folklore. They first appear in Cold Days.

Description
Though labeled the little cousins of Black Dogs, they are described as vicious ambush hunters, and don't like to be spotted while hunting. Harry Dresden reminesces having fought a Black Dog, and not being willing in a repeat.

Cold Days
In Cold Days, Harry Dresden spots three of them ambushing him and his party during their climb to the top; he clips one, and sets on fire the hideout of the second; the third joins them in their flight.