Grimoire Encyclopædia

The demon Agares appears in the grimoires Book of Incantations, The Discoverie of Witchcraft, Book of Treasure Spirits, The Book of Spirits, The Book of the Office of Spirits, The Grand Grimoire, The Book of Oberon, Pseudomonarchia Daemonum, The Lesser Key of Solomon, and Dictionnaire Infernal

From The Lesser Key of Solomon, Crowley/Mathers edition:

Agares

The Second Spirit is a Duke called Agreas, or Agares. He is under the Power of the East, and cometh up in the form of an old fair Man, riding upon a Crocodile, carrying a Goshawk upon his fist, and yet mild in appearance. He maketh them to run that stand still, and bringeth back runaways. He teacheth all Languages or Tongues presently. He hath power also to destroy Dignities both Spiritual and Temporal, and causeth Earthquakes. He was of the Order of Virtues. He hath under his government 31 Legions of Spirits. And this is his Seal or Character which thou shalt wear as a Lamen before thee.