Dragons in World of Warcraft have long been reclusive creatures of mystery; they didn't generally interact with other creatures of the world, with few exceptions. Until the launch of WoW, few chose to speak to the mortal races. The red dragon Korialstrasz was a notable exception who interacted with humans and others quite frequently, even holding a place on several councils in organizations like the Kirin Tor and Silvermoon. However, Korialstrasz took mortal form and the name Krasus when doing so and was careful not to reveal his identity.
The same applies for other dragons prior to World of Warcraft, and even in WoW itself. Chronormu, or Chromie as she's more typically called, often interacts with mortals on behalf of the Bronze Dragonflight. As time has passed in game, however, more and more dragon are interacting with mortals in dragon form, no longer feeling the need to disguise themselves or keep their identities a secret. But once upon a time, this ability to disguise and take another form wreaked havoc among the human kingdoms. It all started with a man named Daval Prestor.