This is awesome. You did an incredible work, and you are right! enormous image! I like how you did the eyes (he seems really mad!!
), better than I said, and I like a lot how you did the wings and the pose is very original like I said before with the sketch.
Also the potatoes can be a rare kind of mineral that they eat (that's because they can "manage" some types of forbbiden magic and also that's because they are mad)
I like also the rest of the details: the head and the end of the tail. Superb work!!