Asmodeus is the king of demons mostly known from the deuterocanonical Book of Tobit (that is to say portions of the Bible not included in the Hebrew version), in which he is the primary antagonist.
The demon is also mentioned in some Talmudic legends, for instance, in the story of the construction of the Temple of Solomon. He was supposed by some Renaissance Christians to be the King of the Nine Hells. Asmodeus also is referred to as one of the seven princes of Hell. In Binsfeld's classification of demons, each one of these princes represents one of the seven deadly sins (Pride, Lust, Envy, Sloth, Greed, Gluttony, and Wrath). Asmodeus is the demon of lust and is therefore responsible for twisting people's sexual desires. It is said that people who fall to Asmodeus' ways will be sentenced to an eternity in the second level of hell.
According to the Kabbalah and the school of Rashba, Agrat Bat Mahlat, a succubus, mated with King David and bore a cambion son Asmodeus, king of demons.
The Asmodeus of the Book of Tobit is attracted to Sarah, Raguel's daughter, and is not willing to let any husband possess her; hence he slays seven successive husbands on their wedding nights, thus impeding the sexual consummation of the marriages. When the young Tobias is about to marry her, Asmodeus proposes the same fate for him; but Tobias is enabled, through the counsels of his attendant angel Raphael, to render him innocuous. By placing a fish's heart and liver on red-hot cinders, Tobias produces a smoky vapor that causes the demon to flee to Egypt, where Raphael binds him.
Asmodeus would thus seem to be a demon characterized by carnal desire; but he is also described as an evil spirit in general. Moreover, it is possible that the statement, "Asmodeus loved Sarah," implies that he was attracted not by women in general, but by Sarah only.
The figure of Ashmedai in the Talmud is less malign in character than the Asmodeus of Tobit. In the former, he appears repeatedly in the light of a thoughtful, good-natured, supportive, and humorous fellow. But besides that, there is one feature in which he parallels Asmodeus, inasmuch as his desires turn upon Solomon's wives and Bath-sheba. But even here, Ashmedai seems more comparable to a Greek satyr rather than to an evil demon.
Another Talmudic legend has King Solomon tricking Asmodai into collaborating in the construction of the Temple of Jerusalem. In yet another legend Asmodai changed place for some years with King Solomon. An aggadic narrative describes him as the king of all of the shades. Another passage describes him as marrying Lilith, who became his queen.
He has also been recorded as the off-spring of the union between Adam and the angel of prostitution, Naamah, conceived while Adam was married to Lilith.
In the Testament of Solomon, a 1st-3rd century text, the king invokes Asmodeus to aid in the construction of the Temple. The demon appears and predicts Solomon's kingdom will one day be divided. When Solomon interrogates Asmodeus further, the king learns that Asmodeus is thwarted by the angel Raphael, as well as by sheatfish found in the rivers of Assyria. He also admits to hating water and birds because both remind him of God.
In the Malleus Maleficarum, Asmodeus was considered the demon of lust, to which agreed Sebastien Michaelis saying that his adversary is St. John. Some demonologists of the 16th century assigned each month to a demon and considered November to be the month in which Asmodai's power was stronger. Other demonologists asserted that his zodiacal sign was Aquarius but only between the dates of January 30 and February 8.
He has 72 legions of demons under his command. He is one of the Kings of Hell under Lucifer the emperor. He incites gambling, and is the overseer of all the gambling houses in the court of Hell. Some Catholic theologians compared him with Abaddon. Yet other authors considered Asmodeus a prince of revenge.
In the Dictionnaire Infernal by Collin de Plancy, Asmodeus is depicted with the breast of a man, a cock leg, serpent tail, three heads (one of a man spitting fire, one of a sheep, and one of a bull), riding a lion with dragon wings and neck, all of these animals being associated with either lascivity, lust or revenge.
Asmodai appears as the king "Asmoday" in the Ars Goetia, where he is said to have a seal in gold and is listed as #32. according to respective rank.
He "is strong, powerful and appears with three heads; the first is like a bull, the second like a man, and the third like a ram; the tail of a serpent, and from his mouth issue flames of fire". Also, he sits upon an infernal dragon, holds a lance with a banner and, amongst the Legions of Amaymon, Asmoday governs 72 legions of inferior spirits.
Asmodeus is referred to in Book Two Chapter Eight of The Magus (1801) by Francis Barrett.
Asmodeus was named as an angel of the Order of Thrones by Gregory the Great.
Asmodeus was cited by the nuns of Loudun in the Loudun possessions of 1634.
Asmodeus' reputation as the personification of lust continued into later writings, as he was known as the "Prince of Lechery" in the 16th century romance Friar Rush. The French Benedictine Augustin Calmet equated his name with fine dress. The French novelist Alain-René Lesage likened him to Cupid in his 1707 novel le Diable boiteux. In the book, he is rescued from an enchanted glass bottle by a Spanish student Don Cleophas Leandro Zambullo. Grateful, he joins with the young man on a series of adventures before being recaptured. Asmodeus is portrayed in a sympathetic light as good-natured, and a canny satirist and critic of human society. Following this, he was depicted in a number of novels and periodicals, mainly in France but also London and New York.
The 16th century Dutch demonologist Johann Weyer described him as the banker at the baccarat table in hell, and overseer of earthly gambling houses.
Asmodeus was widely depicted as having a handsome visage, good manners, and an engaging nature, however, he was portrayed as walking with a limp and one leg was either clawed or that of a cock. He walks aided by two walking sticks in Lesage's work, and this gave rise to the English title The Devil on Two Sticks (also later translated The Limping Devil and The Lame Devil). Lesage attributes his lameness to falling from the sky after fighting with another devil.