Unidentified dragon 3 (The Hearth's Warming Club)

The unidentified dragon was one of the Ancient Dragon Lord's friends or family members.

History
According to a tale told at a Feast of Fire in the during the Reign of Ember and recounted by Smolder, this dragon attended a meal held by the Ancient Dragon Lord. Several other dragons attended, with the the lonely dragon Scales also being invited. Tragically, Scales betrayed their host's hospitality and seized the Bloodstone Scepter, thus ending the Ancient Dragon Lord's reign and beginning her own.

Behind the scenes
This dragon is a simple palette swap of a preexisting character, a common design trick in My Little Pony: Friendship is Magic. Specifically, this dragon is a recolor of "Rex".