Long ago, before the Age of Darkness, in a time when powerful empires of magic ruled the land the arcanatons were first seen on Golarion. Drawn by the confluence of magical power, these creatures are the raw stuff of arcane energy given life and form. Powerful in their own right, when given a source of magic upon which to feed, they become nearly unstoppable.
But times change and empires fall. In the darkness that followed Starfall, much was lost, and as power left the world these creatures of arcane energy withered and died, deprived of the magical power that they needed for sustenance. Only a few linger still, tied to the rare relics of power that still remain from those ancient times.
Long the self-proclaimed masters of magical power, the many races of dragons thrived on Golarion while humanity was still little more than savage beasts. It was they who learned the secrets of summoning and binding these creatures of elemental magic, and they yet remain the dragons' servants, ever watchful for arcane adepts that would plunder the treasures of their masters. When it came time to construct an important symbol of their power, it was inevitable that they would choose to include arcanatons among the Guardians of Dragonfall.
Looking at the list of artists for Guardians of Dragonfall, I'm guessing the art for this blog is by Imaginary Friends Studios, although I do not know which specific artist with that group drew the image.
If it isn't someone from Imaginary Friends Studios, that would leave Wayne Reynolds and Drew Pocza as the remaining contenders according to the credits.