Crest
In the official mazoku hierarchy chart, Zellas is represented with the crest pictured to the left. The symbol in the center of the crest is also the symbol of a Goetia demon named Ipos. Alternative spellings of the name are "Ipes" and his alias is "Ayperos" or " Ayporos.". According to S.L. MacGregor Mathers in his book Goetia (1904):
Ipos is the Twenty-second Spirit listed in the Goetia, who governs 36 Legions. He appears as an angel with a lion's head, a goose's foot, & a hare's tail. He knows of past, present, & future events, & makes men witty & bold.
Pretty fitting for the Beastmaster. In fact, all the mazoku lords have crests from the Goetia demons, and their characters are probably inspired by those demons in the first place.