According to Goetia, Bael is the First Principal Spirit who rules as king of the East.
He has command of over 66 legions of demons, who he speaks to with a hoarse voice. His appearance varies, although the most common is a three-headed apparition, with the heads being a cat, a man and a toad. He is able to make his conjurer invisible.
According to the Grand Grimoire, he is a direct subordinate of Lucifuge.