Stolas

"Stolas is a Great Prince of Hell, commands twenty-six legions of demons (twenty-five according to other authors), and teaches astronomy and the knowledge of poisonous plants, herbs and precious stones. He is also known as Stolos and Solas. He is depicted as either being a crowned owl with long legs, a raven, or a man."

The Great Prince Stolas was summoned by Mordecai Grimsby, a local magistrate, and contracted into lifelong servitude. He often takes the form of a raven but will assume the appearance above if the situation requires something more "human".