1) Goetic demon 
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 ways. 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 ...