Gaap is a powerful demon described as a Prince in human form who incites the love. It is said that Gaap also provides medical care for women, transforms them to make it easier to get to a lover, renders them infertile, and rules twenty-five legions of spirits.
The sources also describe Gaap as a President, giving him the powers to teach philosophy and liberal arts, make others invisible, steal familiars from other magicians, make men stupid, and carry men between kingdoms; in addition to ruling sixty-six legions of demons.
Gaap is also believed to be connected to necromancers, and states that he was first called upon by Noah's son Ham, along with Beleth. He was of the order of potestates.
Gaap is also one of the four cardinal spirits, of the south in the Lesser Key of Solomon, the west in the Pseudomonarchia Daemonum.