In demonology, Crocell (also called Crokel or Procell) is the 49th spirit of the Goetia, manifesting as an angel with a tendency to speak in dark and mysterious manners. Once a member of the Powers, he is now a Duke of Hell who rules over 48 legions of demons. When summoned by a conjuror, he can teach geometry and other liberal sciences. He can also warm bodies of water, create the illusion of the sound of rushing waters, and reveal the location of natural baths.
Demonology is the systematic study of demons or beliefs about demons. ... A conjurer (or conjuror) is a person that performs rituals or acts of conjuration. ...

See also The Lesser Key of Solomon, Ars Goetia. Cover of the 1995 edition of the 1904 Goetia by S.L.M. Mathers and Aleister Crowley. ... The Ars Goetia (Greek, probably: The Art of Witchcraft), often simply called the Goetia, is the first section of the 17th century grimoire Lemegeton Clavicula Salomonis, or The Lesser Key of Solomon. ...