The demon Forneus appears in the grimoires The Discoverie of Witchcraft, Pseudomonarchia Daemonum, and The Lesser Key of Solomon
From The Lesser Key of Solomon, Crowley/Mathers edition:
The Thirtieth Spirit is Forneus. He is a Mighty and Great Marquis, and appeareth in the Form of a Great Sea-Monster. He teacheth, and maketh men wonderfully knowing in the Art of Rhetoric. He causeth men to have a Good Name, and to have the knowledge and understanding of Tongues. He maketh one to be beloved of his Foes as well as of his Friends. He governeth 29 Legions of Spirits, partly of the Order of Thrones, and party of that of Angels. His Seal is this, which wear thou, etc.