In the Platonic, Neopythagorean, Middle Platonic, and Neoplatonic schools of philosophy, the Demiurge is an artisan-like figure responsible for fashioning and maintaining the physical universe. The Gnostics adopted the term "demiurge". Although a fashioner, the demiurge is not necessarily the same as the creator figure in the monotheistic sense, because the demiurge itself and the material from which the demiurge fashions the universe are both considered to be consequences of something else. Depending on the system, they may be considered to be either uncreated and eternal or the product of some other entity.
The word demiurge is an English word derived from demiurgus, a Latinised form of the Greek δημιουργός or dēmiourgos. It was originally a common noun meaning "craftsman" or "artisan", but gradually came to mean "producer", and eventually "creator". The philosophical usage and the proper noun derive from Plato's Timaeus, written c. 360 BC, where the demiurge is presented as the creator of the universe. The demiurge is also described as a creator in the Platonic (c. 310–90 BC) and Middle Platonic (c. 90 BC – AD 300) philosophical traditions. In the various branches of the Neoplatonic school (third century onwards), the demiurge is the fashioner of the real, perceptible world after the model of the Ideas, but (in most Neoplatonic systems) is still not itself "the One". In the arch-dualist ideology of the various Gnostic systems, the material universe is evil, while the non-material world is good. According to some strains of Gnosticism, the demiurge is malevolent, as it is linked to the material world. In others, including the teaching of Valentinus, the demiurge is simply ignorant or misguided.
Gnosticism presents a distinction between the highest, unknowable God or Supreme Being and the demiurgic "creator" of the material. Several systems of Gnostic thought present the Demiurge as antagonistic to the will of the Supreme Being: his act of creation occurs in an unconscious semblance of the divine model, and thus is fundamentally flawed, or else is formed with the malevolent intention of entrapping aspects of the divine in materiality. Thus, in such systems, the Demiurge acts as a solution to (or, at least possibly, the problem or cause that gives rise to) the problem of evil.
In the Apocryphon of John, On the Origin of the World and Hypostasis of the Archons, found in the Nag Hammadi library, Samael is one of three names of the demiurge, whose other names are Yaldabaoth and Saklas. After Yaldabaoth claims sole divinity for himself, the voice of Sophia comes forth calling him Samael, due to his ignorance. In On the Origin of the World his name is explained as "blind god" and his fellow Archons are said to be blind, too. In Hypostasis of the Archons is explained as "god of the blind". Reflecting the characteristics of the Christian devil, making people blind, as does the devil in 2 Corinthians 4. Also Samael is the first sinner in the Hypostasis of the Archons and the First Epistle of John is calls the devil as sinner from the beginning. These characteristics combined with his boasting conflates the Jewish god with the devil. His appearance is that of a lion-faced serpent. Although the Gnostics and Jewish originally used the same source, both depictions of Samael developed independently.
Samael is sometimes confused in some books with Camael, who appears in the Gospel of Egyptians also as an evil power, whose name is similar to words meaning "like God" (but Camael with a waw missing). The name might be explained, because in Jewish traditions, the snake had the form of a camel, before it was banished by God. 
One Gnostic mythos describes the declination of aspects of the divine into human form. Sophia (Greek: Σοφία, lit. "wisdom"), the Demiurge's mother a partial aspect of the divine Pleroma or "Fullness," desired to create something apart from the divine totality, without the receipt of divine assent. In this act of separate creation, she gave birth to the monstrous Demiurge and, being ashamed of her deed, wrapped him in a cloud and created a throne for him within it. The Demiurge, isolated, did not behold his mother, nor anyone else, and concluded that only he existed, ignorant of the superior levels of reality.
The Demiurge, having received a portion of power from his mother, sets about a work of creation in unconscious imitation of the superior Pleromatic realm: He frames the seven heavens, as well as all material and animal things, according to forms furnished by his mother; working however blindly, and ignorant even of the existence of the mother who is the source of all his energy. He is blind to all that is spiritual, but he is king over the other two provinces. The word dēmiourgos properly describes his relation to the material; he is the father of that which is animal like himself.
Thus Sophia's power becomes enclosed within the material forms of humanity, themselves entrapped within the material universe: the goal of Gnostic movements was typically the awakening of this spark, which permitted a return by the subject to the superior, non-material realities which were its primal source.