Gaap (also known as Gäap) is a mighty Prince and Great President of Hell and one of the four kings of the cardinal directions, who rules over the South, commanding sixty-six legions of demons. Gaap is depicted in human shape.
- Gaap controls the element of water and reigns over the Water Elementals or the 'water demons'. He teaches Philosophy and all liberal sciences, can cause love or hate and make men insensible and invisible, deliver familiars out of the custody of other magicians, gives true answers concerning past, present and future, and can carry and re-carry men and things speedily from one nation to another at the conjurer's will. According to a few authors he can make men ignorant.
- He is said to be better conjured to appear when the Sun is in a southern zodiacal sign.
- According to Pseudomonarchia Daemonum, certain necromancers honour him with sacrifices and burning offerings.