The Demon Phoenix (also seen as Phenix, Pheynix) is a Fallen Angel and the 37th of the 72 Spirits of Solomon. Phoenix reigns as a marquis in Hell with 20 Legions of Demons. He appears as a phoenix bird and sings sweetly in a child’s voice. It is really a siren’s voice, and so the magician must take precautions not to be seduced by it. Upon command, Phoenix will assume a human shape and then speak on all the sciences and deliver excellent poetry. He fulfills all commands well. Phoenix has the futile hope that he will return to the seventh throne in 1,200 years. He formerly was in the angelic order of thrones.
From “The Goetia: The Lesser Key of Solomon the King” (1904) Written by S.L. MacGregor Mathers
PHENEX. – The Thirty-Seventh Spirit is Phenex (or Pheynix). He is a great Marquis, and appeareth like the Bird Phoenix, having the Voice of a Child. He singeth many sweet notes before the Exorcist, which he must not regard, but by-and-by he must bid him put on Human Shape. Then he will speak marvellously of all wonderful Sciences if required. He is a Poet, good and excellent. And he will be willing to perform thy requests. He hath hopes also to return to the Seventh Throne after 1,200 years more, as he said unto Solomon. He governeth 20 Legions of Spirits. And his Seal is this, which wear thou, etc.
From the “Pseudomonarchia Daemonum” ( 1583 ) Written by Johann Weyer (Johann Wier)
Phoenix is a great marquesse, appearing like the bird Phoenix, having a childs voice: but before he standeth still before the conjuror, he singeth manie sweet notes. Then the exorcist with his companions must beware he give no eare to the melodie, but must by and by bid him put on humane shape; then will he speake marvellouslie of all woonderfull sciences. He is an excellent poet, and obedient, he hopeth to returne to the seventh throne after a thousand two hundreth yeares, and governeth twentie legions.
Original Text: Phœnix magnus Marchio: apparet uti avis phœnix puerili voce: sed antequam se sistit coram exorcista, cantus emittit dulcissimos: tunc autem cavendum exorcistæ cum suis sociis, ne suavitati cantus aures accommodent, sed ille mox huic jubeat humanam assumere speciem, tunc mire loquetur de cunctis scientiis admirandis. Poëta est optimus and obediens. Sperat se post mille ducentos annos ad septimum thronum rediturum. Viginti præest legionibus.
From the “Dictionnaire Infernal” (edition of 1863 ) Written by Jacques Auguste Simon Collin de Plancy
Original Text : Phénix, grand marquis des enfers. Il paraît sous la forme d'un phénix avec la voix d'un enfant; avant de se montrer à l'exorciste, il renddes sons mélodieux. Il faut au contraire se boucherles oreilles quand on lui commande deprendre la forme humaine. Il répond sur toutesles sciences. C'est un bon poëte, qui satisfait envers à toutes les demandes. Après mille ans, ilespère retourner au septième ordre des Trônes.Vingt légions lui obéissent.
Note From Occult World :
In the Dictionnaire Infernal he only hopes that after 1000 years ( and not 1200 ) he will return to the order of Thrones.