Slawomir has done nearly fifty pieces of art for us so far, and he did five pieces for Theros; let's take a look at each of those five.
The art description for this card left the vast majority of it up to Slawomir. It simply called for "a winged demon aloft in a stormy sky. Harpies circle the sky in the background" and it noted the need for Greek ruins in the background.
For Ember Swallower the art description read, "It has the head and body of a massive hound and three rows of razor-sharp teeth. It has a scorpion tail, which curls up over its back. The beast is massive, at least as big as an elephant." While going on to highlight the prevalence of lava both in the body and pooling underneath from its heat.
To me, this art does a fantastic job of evoking motion and movement. I can almost see the liquid zooming up into the air before coming down and coalescing into a solid form.
My favorite part of this card is how the background night sky is so vivid, I sort of feel like it's popping off the card (and the screen) at me.
I don't think many players have realized but Stormbreath Dragon is based on Typhon, which was the most deadly monster of Greek mythology. He is called the "Father of all Monsters."