Dragon

Dragons come in two variaties in the Dresden Files but so far only the Dragon Ferrovax has been seen once in Grave Peril while masquerading as a Roman Legionary.

Dragons
According to Jim Butcher there are two types of dragons. Dragons "large D" and dragons "little d"

Dragons (large D) are elemental forces of the cosmos in the more asian sense of the concept, semi-divine beings who were once given authority over various portions of the mortal universe, and who were responsible for their orderly procession.

dragons (little d) are smauglike beings, but they are essentially nothing but emissaries and servitors created in the image of the real thing. There are not nearly as many as there were in the past.

Other than Ferrovax, the only in book reference we have to a dragon is also in Grave Peril when Michael Carpenter confirms that he slew the Dragon Sirothrax when he rescued his future wife Charity.

Regardless of big D or little d, dragons almost universally resent humanity for usurping the balance of power in the world.