Marchosias is one of the demons of the Ars Goetia. He's a Marquis of Hell, and comands thirthy legions of demons. He is depicted as a dog with griffin wings and a serpent tail.
In 'The Lesser Key of Solomon' (17th century) Marchosias is depicted as a man, however, in 'Pseudomonarchia Daemonum' (1577), Marchosias is depicted as a woman.
More of Marchioness Marchosias~
This time in her full demon form.
And if you're curious, here are some other related drawings, and the fanfic:
