Stolas is the 36th demon of the Ars Goetia, the infamous demon compendium that is part of a greater Renaissance-era grimoire known as the Lemegeton or Lesser Key of Solomon. He also appears as the 69th demon in Johann Weyer's Pseudomonarchia Daemonum, an earlier text which influenced much of the content of the Lesser Key of Solomon. Variants of his name include Stolos and Solas.
Stolas is usually seen as a crowned, long-legged owl. This form was made famous by the illustrations of Louis Le Breton first included within Collin de Plancy's the Dictionnare Infernal, a 19th century demonology text. Stolas is also said to take the guises of either a raven or a man.
Stolas is given the title of a Great Prince of Hell, or sometimes simply Prince. Like all the other demons of the Goetia, Stolas commands a particular number of demonic legions, specifically 26. His duties and skills are described consistently across the Goetia, Pseudomonarchia Daemonum, and the Dictionnaire Infernal, and describe Stolas as bearing superlative knowledge of astronomy, the value of precious stones, and the effectiveness of herbs or poisonous plants. He will impart that knowledge to those who summon him.
The 1583 edition of Weyer's Pseudomonarchia Daemonum gives the following description to Stolas:
Stolas is a great prince, appearing in the forme of a nightraven, before the exorcist, he taketh the image and shape of a man, and teacheth astronomie, absolutelie understanding the vertues of herbes and pretious stones; there are under him twentie six legions.
The 1904 translation of the Goetia by S. L. MacGregor Mathers describes Stolas similarly to the Pseudomonarchia Daemonum, showing the latter's influence:
The Thirty-sixth Spirit is Stolas, or Stolos. He is a Great and Powerful Prince, appearing in the Shape of a Mighty Raven at first before the Exorcist; but after he taketh the image of a Man. He teacheth the Art of Astronomy, and the Virtues of Herbs and Precious Stones. He governeth 26 Legions of Spirits; and his Seal is this, which is, etc. (see accompanying image)
In video games
Stolas has made minor appearances primarily in the Castlevania and Megami Tensei series.
Stolas appears as a regular enemy in the final areas of both Castlevania: Aria of Sorrow and Castlevania: Dawn of Sorrow. In Aria of Sorrow he attempts to interfere with Soma Cruz's progress in the Top Floor of the castle and within the Chaotic Realm by slowly walking forward whilst summoning Dead Crusaders or Red Minotaurs. Stolas appears in Aria in typical form as a owl with a stout body and long legs, and his animations include spinning his small, crowned head in a complete 360 degree circle. In Dawn of Sorrow his home is within the hellish Abyss and he performs similar summoning attacks. Stolas' profiles within both games stress his aged wisdom.
Stolas makes a bevy of minor appearances in the Megami Tensei series, as early as the first title, Digital Devil Story: Megami Tensei and its remake in the Kyuuyaku Megami Tensei compilation. In both those games and Last Bible III, he goes by his alternate name Solas. He also appears in the Devil Children subseries and in the English localized DemiKids titles, his name was given as "Talon."
His most notable appearance in Megami Tensei is in the 1995 Saturn title Shin Megami Tensei: Devil Summoner where he is a level 9 member of the largely Goetia-themed Fallen race and is its weakest representative in that game, with basic skills like Dia the initial tier of the rarely-seen Psy element. Illustrated by series artist Kazuma Kaneko, this version of Stolas hews close to the tradition of Louis Le Breton and depicts the demon as a blue, long-legged owl adorned with a crown. This design of Stolas has so far only appeared in one other game in the series, the Game Boy Color card battle game Shin Megami Tensei Trading Card: Card Summoner.
Aside from the Devil Children series, Stolas' technically latest appearance in a main Megami Tensei title is in the PC exclusive Giten Megami Tensei: Tokyo Mokushiroku, where he is part of the "Futenshi" race of fallen angel demons that exists in addition, and is essentially analog, to the typical Fallen clan. In it, his sprite is a raven brandishing a sword, one shared with other Goetia birds in the game including Halphas and Andras.