Thank you.  Author of the series is Jim Butcher, the same guy that writes the Dresden Files.  Six book in the cities.   The whole series was conceived by an AMA on redit when Jim was asked if he could write a successful book based on one bad idea.   He countered that he could not with one bad idea, but he could do so with two.  A poll was taken and the two bad ideas selected by Jim were Pokemon, and the lost Ninth Roman Legion.   It is an excellent series and I do recommend it.  Audio books are narrated by Kate Redding, who I am a fan of as she does the Wheel of Time books for audio books as well.