Zacal is a rare creature in the sense that he was once a demon, but turned his back on his heritage and swore to serve the Courts of Divinity instead. (Alternately, his brother, Yxlan, is one of the most feared demons of Mahar.)
Trusting him to live up to his word, the Diamond Court placed Zacal at the forefront of the Silver Court, the dominion of the Greater Beasts, and was charged with protecting these creatures. In mythology he was known as the Prince of Shape-Shifters, patron of the wilderness, and rarely made himself seen by mankind.
Perhaps his demon heritage caught up with him at last, or maybe he was justified in his actions. The humans grew to compete with the greater beasts over land and food, and eventually started trying to lkill the creatures off altogether. Zacal, in a fit of madness, decided that humans were a plague upon the land and led his remaining beasts into a bloody war with humans and their villages. Though the Diamond Court agreed that the humans' attack of the Greater Beasts was a crime, the believed that Zacal had taken his revenge a little too far, and eventually the Diamond Court stepped in to protect the humans from further harm. The Silver Court, enraged and feeling betrayed, turned on their Diamond Court benefactors, and a nasty war between gods ensued. Before the war was ended, all but a couple of Greater Beasts were slain, and Zacal disappeared, consumed by grief and anger. Some claim he went back to Mahar to return to life as a demon, but most folks claim he simply withered away and died.
The truth, however, is that Zacal has survived through the ages since his war ended, and has lived in exile undetected, skulking about in the guise of one of the lesser beasts, fading from memory. The passing centuries have given him plenty of time to make his new move in the continuing war between the gods.
This picture shows Zacal and his true colors- how he appears when he is not shape-shifted. He is not a pleasant (nor sane) creature to be around.