Due to the influence that Gnosticism has had on popular media and Christianity itself in recent decades, an examination of the basic beliefs of the Gnostic worldview would be helpful.
In the beginning was nothing but a single consciousness. This primordial awareness had no content, as there was nothing in existence of which to be aware. It existed in a timeless, thoughtless state analogous to the Buddhist experience of Nirvana.
The two minds, one male and one female, interacted creating a pantheon of deities known as aeons, who inhabited a divine realm of light known as the "Pleroma".
The most distant aeon from the Source, named Sophia (Greek for "wisdom"), fell into error. Some versions say that she tried to emanate a universe without her male counterpart, others say that she tried to take on the mind of the Source in its entirety. Whatever the reason, she fell out of communion with the rest of the aeons and became trapped in the primordial material universe. Some say that Sophia was destroyed and her remnants would become human souls.
From the matter that solidified out of her divine power, a False God was born, known as the Demiurge or Yaltabaoth, the Gnostic equivalent of Azathoth. The Demiurge then creates the Universe that is isolated from the higher dimensions above.
The reason why suffering and evil exist in this world is because it is actually governed by this flawed Demiurge who mistakenly believes himself to be the absolute God. This is the deity worshiped by many Abrahamic religions (Judaism, Christianity, Islam and others) who are materialistic, vicious and not in possession of true spiritual wisdom. Analogous to Mahabrahma in Hinduism and some forms of Buddhism, who also mistakenly believes himself to be the ultimate authority while the rest of the gods snigger behind his back.
Human minds and souls are sparks of divine light from the Pleroma, who are trapped in the material universe and who must endeavour to free themselves and their kin from the misery of matter. Some versions say the Demiurge originally created a bunch of soulless apes out of matter, and that Sophia took pity on them and breathed sparks from the Pleroma into them, only to have the sparks become trapped in the material bodies, but also giving the bodies the capacity for intelligence, hence the evolution of humanity. Others say that the sparks were the destroyed remnants of Sophia herself, imprisoned and tortured by the Demiurge. Sometimes also considered a reinterpretation of the story of Genesis, with Sophia herself as the Tree of Knowledge/Prometheus-equivalent (her name implies that role) who gave intelligence and souls to the ignorant animals who then became mankind.
The Demiurge, and his created servants the Archons, manipulate humanity into violence and misery to feed themselves and further their egotistical projects.
The Messiah came to Earth to spread the Gospel of the True God, explaining the discrepancy between the Old and New Testaments. Gnostic beliefs about Jesus' nature varied radically. Some believed he was fully divine and his physical form an illusion. Some believed he was a divine being who temporarily inhabited a human shell and was "freed" at death, others say he was the intended counterpart of Sophia who came too late. With the true knowledge of the universe he imparted, others could hope to achieve the same divine state.
The essential nature of the universe is an illusion, and the essential task of humanity is to both demonstrate love and compassion and strive to escape from materialism. Gnosis is a specialized form of experiential knowledge that comes to a human being when they recognize the universe as being fundamentally similar to a dream, hologram, or illusion.
However, it is important to remember that Gnosticism at no point constituted a monolith. Different groups would hold doctrine that mixed-and-matched or varied from the above list in their own ways. Gnosticism was also highly syncretic, tending to merge with any other religion it came into contact with creating a new Gnostic sect of that religion or forming a new religion altogether. It was also highly secretive, being practiced mostly by elites who had the leisure time necessary to contemplate its mysteries. Although it is largely extinct today, remnants of it still leave influences. Much of what we know about the Gnostics if fairly fragmentary, few of their original works survive to this day. Furthermore, much of what we have learned about the Gnostics comes from early Christian writings which often critical of these perceived "heretics."
Because the Gnostics had largely died off as a movement during the Middle Ages, there was no one to preserve their texts through reproduction, and many of their texts were lost through time. Until the 1950s, most of what was known about the Gnostic religion as it flourished in ancient times came from the writings of its detractors — such as St. Irenaeus of Lyons, who wrote a five-volume work Against Heresies in AD 180, explaining what the Gnostics believed and why it conflicted with Christianity. That is, until a remarkable event took place in the Egyptian desert. Two brothers digging for fertilizer in a cave on their way to avenge their father's murder discovered an earthenware jar that contained an ancient book. Before realizing its value, some of the text was used for kindling by the family, but they eventually realized its age and sold it to a collector in Cairo. The manuscripts were split up and traded all over the world. Amazingly, the recovered manuscript contained dozens of books written in Coptic that were still in legible condition. Take a look over here if you'd like to read English translations of the Coptic texts yourself. Standouts include
The Gospel of Thomas
The Gospel of Mary Magdalene
The Hypostasis of the Archons
On the Origin of the World
The Thunder, Perfect Mind
This breed of Gnosticism spread into North Africa and the Middle East within 100 years of Jesus' life. It is heavily influenced by Egyptian polytheism, and provides a structure and hierarchy of the Heavens based on Egyptian theology. Tends to be extremely oppositional to Earthly authority, reflecting contempt for the Roman occupation. This form spread east in subsequent years, giving rise to religions like Mandeanism and Manicheanism. Some of their texts can be found here.Valentinian
This tradition was deeply influenced by Valentinius, who was a former Bishop of the Marcionites, another offshoot of Christianity. It was a deeply ecumenical school, which preaches universal salvation of all sentient beings. Even the malevolent Demiurge will eventually be rescued from his ignorance, as all things containing the spark of creation are inexorably moving towards redemption. Essentially, the Lighter and Softer flavor of Gnosticism.
This is a sect that grew out of Gnostic beliefs in France. There are two major theories as to where they came from—the first is that Gnosticism spread into France very early on, the second being it was brought back by Crusader knights who were influenced by Sufism and other Holy Land mystical faiths. Either way, Catharism became very influential in southern France and amassed a fair amount of wealth, castles, and prestige. This development eventually came to challenge the Catholic Church, who felt threatened by the purity and poverty vows that many Cathars took. For those who were bugged by how the Catholics didn't burn other similar monasteries and condemn Jesus' encouragement of such, remember in those days the Catholic Church was exceedingly corrupt and irrational, and the Cathar ascetics were making them look rather bad. So, the usual campaign of book burning and priest killing was embarked upon with the usual devastating consequences.
A God Am I: The Demiurge, who mistakenly believes himself to be the absolute authority. He has the power to create and destroy worlds, but he is still the lowest totem on the celestial pole, beneath the insight of even enlightened humans.
A Kind of One: Three Phoenix are described On the Origin of the World.
All Myths Are True: Gnostic cosmology is a hybrid of personal experience and self-conscious mythology—it's a worldview that seems capable of assimilating any supernatural creature or miracle it runs into. The original Gnostic scriptures seem to contain a patois of Greek philosophy, Egyptian paganism, and Judeo-Christian tradition.
All There in the Manual: The Gnostic scriptures are the manual that contain all the knowledge needed for salvation by gnosis. Unfortunately, big chunks of the manual are lost.
Alternate Character Interpretation: And how! Gnostic scriptures such as "On the Origin of the World" contain a radically different exegesis of Abrahamic traditions. The Creator is ignorant and malevolent, the Serpent in Eden was Sophia (or Jesus,) Noah was a faithless jerk, and the Creator's angels are agents of violence and repression.
The Gospel of Judas has Jesus specifically instructing Judas to betray him, and Judas Wangsting about it.
Thomas, not John, was presented as Jesus' favored disciple.
Or alternately, Mary Magdalene. Who is also sometimes implied to have a romantic relationship with Jesus. Probably not sexual though—the Gnostics were really into asceticism.
Alternate Continuity: The reason for the suppression of the Gnostic teachings by the Roman Catholic Church.
In Mandaeism (an ancient Gnostic-like non-Christian religion, once significant in numbers but now a small group found primarily in parts of southern Iran and Iraq) Jerusalem is considered a city of wickedness, dedicated to the god of Judaism, whom they call Adunay (Adonai) or Yurba (possibly YHWH) and consider to be an evil spirit. According to Sidra d-Yahia 54, Jerusalem is "the stronghold that Adunay built ... [he] brought to it falsehood in plenty, and it meant persecution against my tarmidia (Manda d-Hiia's disciples)." In the Ginza Rba (15.11), it is said to have come into being as a result of the incestuous union of the seven planets with their evil mother Ruha d-Qudsha, who "left lewdness, perversion, and fornication in it. They said: 'Whoever lives in the city of Jerusalem will not mention the name of God.'" (Elsewhere, however, it more prosaically says the city was built by Solomon.) However, Yahya (John the Baptist), an important figure in the religion, is said to have been born there.
Celibate Hero: Possibly hinted to be averted in the Nag Hammadi. A curious passage in the Gospel of Philip has a disciple asking Jesus, "Why do you love her more than us?" after Jesus and Mary Magdalene share a kiss. Jesus sardonically replies, "Why do I not love you like I love her?"
However, the Cathars were encouraged to avoid sexual relationships, and the Perfecti (the ascetic elders of Catharism) were strictly chaste.
Celestial Bureaucracy: There is a complex hierarchy of both angels and demons, and there are even references to the administration of the Demiurge.
Chaotic Good: The Aeon Christ (not to be confused with his persona, Jesus).
Child Eater: According to the ancient Christian writer Epiphanius, at least one Gnostic sect (the Borborites) ritually consumed aborted fetuses as part of their secret ceremonies. However, some modern scholars doubt the reliability of his account.
Cosmic Retcon: The approach of Gnostic scriptures to preexisting Abrahamic views.
Crap Saccharine World/Crapsack World: Depends on people's lot in life and various other factors effecting how they view the world. Crapsack if their life is obviously bad, Crapsaccharine if deceptively good.
Crossover Cosmology: The original Gnostic scriptures included many themes from Kemetic and Abrahamic religions, as well as Greek philosophical developments. Modern tales with a Gnostic bent tend towards All Myths Are True.
Manicheanism attempted to combine Christianity, Zoroastrianism and Buddhism, Mani believing the work of their founders was not yet complete.
Crucified Hero Shot: Averted, subverted, mocked, and even played straight. Some tellings have Jesus lacking a material body, making his crucifixion an illusion. In others, he trades places with a man named Simon of Cyrene and then stands aside laughing as Simon slowly dies. However, the orthodox Christian position was also held by some.
Dawn of an Era: Sophia will return with Jesus, redeem the souls trapped in the material universe, kick the asses of the Evil God and his Archons, then there will be cake.
Demonization: To Platonists the Demiurge was a perfect image of the supreme good and the archetype of all existing things. Any perceived imperfections in the work based off of it were just natural decay as things got further away from the source and this decay was not impossible to correct. They were not amused by most gnostic teachings of an evil Demiurge and the universe it made as a Crapsack World, especially Plontinus who pioneered much of the cosmology.
It also demonizes the Platonist Stars Are Souls idea by making the stars evil rulers instead of heavenly homes for those who live justly.
Dirty Coward: The Gnostics were considered this by many because, unlike early Christians such as Ignatius and Polycarp, they were not prepared to suffer martyrdom for their faith.
Epiphanic Prison: The material universe. The general gist of it is that the universe wasn't created by God but Her misguided offspring, the Demiurge. Human souls are trapped in the material world and must, through mystical experience, learn the right secrets (hence "gnosis", "knowledge") that will get them past the Archons after they die, so that they can ascend to the higher, spiritual reality where the true God resides and souls originate.
Evil Is Cool: The Gnostic sect of the Cainites, who — you guessed it — took their name from the first murderer. They believed that since the God of the Bible was evil, everyone who opposed him must be good, so they took up Cain, Pharaoh, the people of Sodom and Gomorrha ... basically every villain in the Old Testament ... as their heroes and role models.
It should be noted that they are A Lighter Shade of Black in Evil Versus Evil agianst the Demiurge. It should also be noted that the Demiurge was the Magnificent BastardManipulative BastardThe Chessmaster who used a Xanatos Gambit to orchestate their Start of Darkness. This is especially with regards to Cain and Pharaoh. Cain was pushed over the edge to killing his brother Abel because the Demiurge liked him better. Actually, the Demiurge creates several enemies using this same "love the younger brother, hate the older brother" strategy ie love Abel hate Cain, love Isaac hate Ishmael, love Jacob hate Esau, love Judah hate Israel, etc. The Pharaoh was needed to play the role he did because the Demiurge was really really invested in a 400+ year old Xanatos Gambit to cause the Exodus. Simmilar to God On Trial if you think about it. Sodom and Gommorah because of Arson, Murder, and Jaywalking because of the jaywalking part ie deviant sexuality which is one of the Demiurge's Berserk Button.
Evil Is Sexy: Averted, the Demiurge (Big Bad) is a lion headed serpent who is also really ugly. Unlike modern Christian interpretations of evil, evil in Gnosticism is usually boneheaded and bureaucratic in nature, more like a supernal Soviet Union than a whorehouse. Its paragons have unattractive names like "Quarrelsomeness" and "Bitter Weeping."
Also inverted, with Sophia, who is always depicted as beautiful and generally depicted as naked.
Also, this belief has been considered heretical several times. Also, ask any follower of a traditional religion about heaven. You will likely get a lot of descriptions that assume that people have bodies in heaven. Even though some will give a description of heaven consistent with this view.
God Is Evil: The Creator of our world, the Demiurge, is presented at best as ignorant and petty, and at worst as a megalomaniacal sadist.
God Is Good: The Monad. Sort of. It is described in the Apocryphon of John as being without quality or quantity, not partaking of goodness but far surpassing it.
He-Man Woman Hater: Gnostic opinion of femininity varies. Some groups held it equal to maleness but those who presented it as negative it tended to comically do so.
I Have Many Names: The Monad and the Demiurge. The Monad is also known as God, the One, the Absolute, the Reality, the Ultimate Reality, Aion teleos, the Perfect Aeon, Bythos (another Aeon has this name as well), Pro Arche, He Arche, the Ineffable Parent, etc. The Demiurge is also known as Ariael (Hearth God, Lion God), Saklas (Fool), Sammael (Blind God, Senseless God, Satan), and Yaldabaoth (Come Child).
I Kiss Your Hand/I Kiss Your Foot: Jesus to Mary Magdalene in the Gospel of Philip, but where he kissed her is missing in the lacuna where just the location is missing and the rest of the text before and after it is intact.
Jesus Was Way Cool: No matter what their interpretation of Yahweh, all branches of Gnosticism present Jesus as an emissary of the good God.
The one exception to this are the Mandaeans who hold Jesus to be a false messiah who perverted the teachings of the prophet John the Baptist, the main figure of the religion. Interestingly despite the heresy Mandaeism is the sole historic gnostic sect which remains extant.
Light is Good/Light Is Not Good: On one side, there's the Aeons, whole live in greater realms of light. On the other, there's the Archons, who are pretty much evil angels, and one of them is a solar deity.
Missing Episode: Almost the entire written record of the religion, but for the chance discovery of the Nag Hammadi texts in 1945. Still, many other scriptures are referenced in this extant collection that have not been recovered.
Moral Dissonance: Gnosticism tries to solve the problem of God's apparent tyranny in the Old Testament by subverting it completely and presenting the Old Testament God as the equivalent of Satan.
More than Mind Control: Essentially the only power of the Archons and Demiurge is their ability to create illusions, that we souls subsequently participate in and give power.
The Church Father Irenaeus of Lyons alleges that a Gnostic cult leader named Marcus used this on his congregation to gather followers.
The Multiverse: The material universe is the heaviest and slowest projection of divine energy. Interpenetrating matter are increasingly subtle Heavens, each one an order of magnitude more vast and energetic than the last.
One Steve Limit: The Monad has Bythos as on of his/it's names as well as a female Aeon who also has Bythos as her name. Another male Aeon has the name Bythios (an extra i sort of mankes it not the same name).
Original Man: Some discourses describe the original human race as already dwelling amongst the worlds of light with the aeons while man on Earth is just a copy the demiurge made when he saw one of them and did not understand what he was looking at. Since Manichean religion is often grouped with gnostic religion it is worth noting that Mani's original man was created by God to defend creation from the Anti god's invading forces. Modern man is an accidental result of the Anti god's invasion. You may be an inferior copy/thing that should not be but Jesus loves you anyway.
Our Angels Are Different: The Archons, who are the Demiurge's agents and forces of oppression; the most notable appearently correspond to the planets of the solar system, forming a group of seven entities alongside the Demiurge, called the Hebdomad. The Aeons can also be called angels, though they are technically more like gods. Some systems include actual angels who tend to rank below Aeons and become imprisoned in the world of matter though were a little quicker to realize things were not right than humans were, as well as the first to recognize Jesus for what he was.
Pieces of God : The original single consciousness is now split into infinite conciousnesses.
Perspective Flip: The Nag Hammadi neatly presents Yahweh as the opposite of everything he's ever claimed to be. Well, except a jealous, violent dictator.
Pride: The Tripartite Tractate states Logos created the universal defects who are responsible for most of the evil in the universe through mistaken pride that he could create as well as God. He and the other aeons were at a loss at how to handle the defects Logos accidentally created until Jesus came from the father to help them.
Rage Against the Heavens: Certain forms of dualism make the assertion that the thing worshiped as God in this world is actually an evil impostor, but that a true benevolent deity worthy of being called "God" exists beyond this world. The Gnostics believed that God (the deity worshiped by Jews, Greek Pagan philosophers like Platonists and Christians, you could also include Muslims) was really an evil creator or demiurge that stood between us and some greater, more truly benevolent real deity — although there is no reason given why the higher deity is not a creator-god as well, nor why the higher deity allows the realm of the evil demiurge as flawed and unjust to continue to exist. Similarly, Marcionites held beliefs deemed maltheistic in nature, depicting God as represented in the Old Testament as a wrathful, genocidal, malicious demiurge.
Reader Gender Confusion: The Monad based on all of it's genderless descriptions gets confused by being listed with the male Aeons in the family tree of Aeons.
Also, the Aeon Metricos/Metrikos (Maternal/Mother) is the Anthropomorphic Personification of motherhood and maternality despite being listed as a male Aeon.
Really 700 Years Old: Norea, who is the twin sister of Seth and eventual wife of Noah. It doesn't say when she dies, but you can infer she lived a really long time. It's easily longer than either Methusaleh or even Cain.
Satan Is Good: Since Gnostics seek gnosis, that is, spiritual knowledge, many believe that the tempting serpent in Eden was really the spirit of Jesus (sometimes Sophia or her servant Ophis) trying to redeem humanity with knowledge. Luciferianism is a belief system that venerates the essential characteristics that are affixed to Lucifer. The tradition, influenced by Gnosticism, usually reveres Lucifer not as the Devil, but as a liberator or guiding spirit or even the true god as opposed to the Demiurge.
Gnostics had a complex relationship with the devil. Opinions on the devil, and his relationship to the Demiurge, varied. The Ophites held that he and his demons constantly oppose and thwart the human race, as it was on their account the devil was cast down into this world. According to one variant of the Valentinian system, the Demiurge is besides the maker, out of the appropriate substance, of an order of spiritual beings, the devil, the prince of this world, and his angels. But the devil, as being a spirit of wickedness, is able to recognise the higher spiritual world, of which his maker the Demiurge, who is only animal, has no knowledge. The devil resides in this lower world, of which he is the prince, the Demiurge in the heavens; his mother Sophia in the middle region, above the heavens and below the Pleroma. The Valentinian Heracleon interpreted the devil as the principle of evil, that of hyle (matter). As he writes in his commentary on John 4:21, The mountain represents the Devil, or his world, since the Devil was one part of the whole of matter, but the world is the total mountain of evil, a deserted dwelling place of beasts, to which all who lived before the law and all Gentiles render worship. But Jerusalem represents the creation or the Creator whom the Jews worship. . . . You then who are spiritual should worship neither the creation nor the Craftsman, but the Father of Truth. This vilification of the Creator was held to be inimical to Christianity by the early fathers of the church. In refuting the views of the Gnostics, Irenaeus observed that "Plato is proved to be more religious than these men, for he allowed that the same God was both just and good, having power over all things, and Himself executing judgment."
Save the Villain: At least in Valentinian Gnosticism, it's expected that eventually even the most wicked people and deities will be redeemed. Some books, however, do say quite clearly that not all humans even have souls that can be saved.
Also, it sort of helps that the Demiurge and the Archons are categorized as belonging to the psychics group and not the hylics group.
Secret Identity: Several of the female Aeons have a penchant for disguises.
Sex Is Evil: Gnostics were a diverse group and had equally diverse opinions on sex. Some were strict ascetics and believed that sex, masturbation, and even wet dreams were vile temptations of the material plane. Others thought sex was a normal part of creation (Sophia and all that) and indeed the world was created through a kind of sexual relationship between dimorphic aeons. And yet more Gnostics were antimonians who believed that all rules were created by an evil God to control his subjects, and so every single sin must be committed before a human can escape from the prison of the world. Whew!
Actually, we only know of the anti-nomian sects from Catholic and Orthodox theologians. Whether they existed in fact is up to debate.
Some Gnostics believed that the material world was a harsh and evil place, and therefore it was sinful to have children.
Tangled Family Tree: The Aeonic family tree of generational emanations. Note: This list is the fusion of various sources ie Valentinius, Valentinians, Tertullian (Hereseologist), Ptolmey, Colorbasus, etc. Some lists list their names all in Greek, some lists traslate some names into Latin. Different lists sometimes give different meanings to each name. Also, other Aeons like Abrasax/Abrasax, Barbelo, etc. aren't list in the family tree.
The Monad (The One)
The Monad (The One) & Bythos (Depth/Profoundity) Charis (Grace/Love) Enonoia (Intent/Thought) Sige (Silence)
The Übermensch: Some of the Aeons have been know to act like this and to encourage other too.
The Unfettered: Jesus' sin is an illusion speech in the Gospel of Mary.
Through the Eyes of Madness: Gnosis, or personal revelatory experience, is often interpreted by the psychological profession as schizophrenia, due to the incompatibility between theophony and a strictly materialist viewpoint.
Turned Against Their Masters: The Archon Sabaoth, who was created to preside over the Sixth Heaven, renounced the Demiurge in disgust upon hearing the voice of Sophia and discovering that the Demiurge was not the ultimate authority he claimed to be.
Unreliable Narrator: Heresiologists were dismissed by academics for awhile. The finds at Nag Hammadi showed they got a lot of the cosmology right (though they went out of their way to make it sound stupid).
Many recent works, especially those of a postmodernist and existentialist bent, reflect Gnostic influences (whether unconsciously or intentional). Characteristic, though not always, of the Gnostic worldview are vast (and often contradictory) cosmologies, uncertainty, unreliable narrators, and the value of personal interpretation. Protagonists slowly come to the realization that the world is not quite what it seems—they are privy to secret, inside information about reality. Due to the reliance on personal revelation implicit in Gnosticism, it is not surprising when multiple narratives tell the same story without quite lining up. Reason is presented as but one tool that humans can use to understand the world, but logical reasoning is not the whole truth. Examples may range from containing some elements/influences to outright endorsement/promotion. These include:
Anime and Manga
Neon Genesis Evangelion mixes Gnosticism with both the Kabbalah (a Jewish Gnostic variant that proposes we are all pieces of Adam Kadmon) and a mystic reinterpretation of the Jewish story of Genesis where Adam's original first wife wasn't Eve, but Lilith, who fell into error (Sophia-equivalent) thus paving the plot for Eve's creation, humanity's acquisition of the Fruit of Knowledge and the resulting Fall of Man from Eden into biological bodies. Some versions say Lilith or Sophia was the Tree of Knowledge or at least gave the Fruit of Knowledge to Eve in the first place (the Retcon of the Serpent as Big Bad Lucifer was due to Word of Dante and Christian "ignorance is bliss" ideology), if you would consider the theory that Sophia gave a part of herself to humans as souls resulting in the evolution of human intelligence.
Rei Ayanami, the soul of Lilith, the original mother of all humanity, is Sophia, and as The Philosopher lives up to that symbolism. Her flawed fragmented daemonic children, the Lilin (humans) are the Demiurge, technological creators capable of cruelty against each other, after all Hell is Other People. The referral to humans with such a daemonic name is likely from a Gnostic influence. The fall of Sophia (Lilith/Rei, who literally fell to Earth) is responsible for the birth of the Demiurge (the evolution of biological life, and the suffering that it has brought), but Sophia's fragments still exist in this world in the form of our souls (humanity as the bearer of the Fruit of Knowledge), and thus it is possible to redeem ourselves from our daemonic existence (human individual bodies and prone to disease, despair and death) and reconcile with her. The central dogma of an Ancient Conspiracy called SEELE is the reunification of Lilith with her lost male counterpart, Adam (analogous to reuniting Sophia with her lost male counterpart), that shall lead to their Messianic Ascension and Universal Salvation from their Original Sin of existence under the Demiurge/Lilin/Human Bodies. In the End of Evangelion, it does happen: Rei absorbs Adam, takes control of Lilith, reawakens, turns into a Giant Naked Rei/Adam Kadmon/Sophia, destroys all human bodies, and merges all souls into a gestalt God-superconsciousness.
Neon Genesis Evangelion does more research than people give it credit for, but the Gnosticism is almost certainly an accident.
A popular Epileptic Tree about The Melancholy of Haruhi Suzumiya is that Haruhi, as the unconsciously cruel and capricious creator of the material universe, is the Demiurge, and in fact, the real unconscious God is the narrator, Kyon. Haruhi aka the Demiurge is either an aspect of his personality, or a convenient person to work his power through. Note his dialogue at the beginning of the series; he once wanted to believe in time travel, aliens, and espers, but has learned to suppress it. Having someone else have god-like powers to create these things allows him denial. Plus, what better way to throw someone off of their own powers to destroy everything than by telling them to keep someone else in check. In Haruhi theology and fandom, "Kyon is God" theories are the equivalent of Gnosticism.
Fullmetal Alchemist mixes Gnostic elements with Eastern and Jewish Kabbalah influences plus Cosmic Horror Story. It's also subverted, considering how unpleasant it is dealing and facing the Truth.
Texhnolyze: The further into this series you get, the more Gnostic symbolism and saturation shows up, with some of the darker and more paranoid ideas becoming increasingly warped and played with in a highly Mind Screwy manner. For example, the disturbing way in which Doc increasingly mirrors Sophia, or Kano mirrors the demiurge. And then of course, there's Ran.
Who Kano keeps calling "Theoria" for no obvious reason. Naturally, this is yet another Gnostic concept meaningless to a casual viewer.
In A Certain Magical Index, some of the magical characters are surprised when they learn of Academy City's ambition to create a Level 6 Esper; it may be a scientific project, but the concept is similar to teachings in Gnosticism.
Puella Magi Madoka Magica The Movie: Rebellion has Homura turn into a sort of a mixture of the Demiurge, Mara, and a Paradise Lost-like Lucifer: she becomes corrupted by love and rips Madoka, the proper God of the setting, from her position and takes her power herself, trapping all of the characters in a magical world where their desires have been granted but their true powers and nature suppressed. Notably, this Demiurge is not a piece of the Source, but a servant of it who takes its place in order to protect it.
The Silmarillion should be counted in because of the "spiritual" hierarchy, beginning with Eru, supreme being, creating the Ainur, split in the Valar and the Maiar, then the Elves, and finally Humans. The tale is also gnostic because it states that while the world was created by Eru, the greater Ainur gave it form, and one of them (Melkor), broke out and claimed it for his own, being "the lord of the world". Maybe the linguistic way from Eon to "Ainu" is not that long after all.
Anything written by Philip K. Dick, who had a keen sense of the existential paranoia implicit in the Gnostic scriptures and a working knowledge of the recently-translated Nag Hammadi codices (and don't forget the I Ching). Particularly of note are VALIS, The Divine Invasion, The Transmigration of Timothy Archer, and Radio Free Albemuth. However, perspective readers should be warned about the high Mind Screw content and the possibility of their brain turning to liquid, pouring out of their ears, and reassembling itself in a smiley face twenty-five kilometres over the peak of Kilimanjaro—and no, that's not a highly confusing metaphor for insanity.
God have mercy on our souls, but Dan Brown has done as much to raise Gnosticism into the public consciousness as the Wachowskis.
It might be useful to point out that while the Wachowskis have ushered Gnosticism into the public consciousness through the underlying philosophical discussions in their films note with said discussion reaching into the fundamental ideology of Gnosticism and debating the arguments for and against the probable nature of reality, the delineation of the borders of reality, and playing with the idea of the demiurge and assessing sentient beings as contributors to the formation of an imperfect consensus reality, Dan Brown has raised awareness of Gnosticism by flinging the term around so liberally in such a vague and arbitrary manner in his books that it drove most of his readers to look it up on The Other Wiki... where most of them found two things: 1) Gnosticism is incredibly detailed, ancient, and so deep and involving that you can spend days on a Wiki Walk just scratching the surface, and 2) Dan Brown has a very bad habit of Completely Missing the Point when it comes to secular and philosophical ideology.
Unfortunately, the "gnosticism" presented by Dan Brown in his books tends towards the polar opposite of actual Gnostic beliefs as expressed in their scriptures. He says they believed Jesus was completely human; Gnostics actually tended to think Jesus was completely god without a trace of the human. Dan also thinks the Gnostics respected women, which, while true of many Gnostic sects, was far from universal; a good number of Gnostics actually tended more towards the Greek idea that women were an inferior form of life incapable of spiritual understanding.
Some works of Iain Banks slide into this area in varying degrees, of note in The Culture novels are Excession, Look to Windward, and Use of Weapons. In other books, The Algebraist is pulled deeply into Gnostic territory with a dark and snarky bent.
You have to look pretty hard, but it has increasingly been suggested that Paradise Lost draws on Gnostic theology.
In a meta example, the literary critic Harold Bloom developed Gnostic theory of artistic influence wherein new generations of poets seek to construct the predecessors as controlling antagonists against whom they can react.
Daniel Gonzalez science fiction short-story Sofia is about a parallel universe where Gnosticism and not Christianity became the world’s main religion. He gives a lot of information about Gnostic history, terminology and doctrine.
Creation Man And The Messiah by poet Henrik Wergeland is by far the most gnostic piece of literature written during the 19th century, telling how higher spirits intervened to ensoul humanity. The spirits are called Eons (or aions) here as well.
LOST's mythology and underlying metaphysics were heavily rooted in Gnosticism, but the show never drew any explicit parallels to it except for a brief glimpse of Philip K. Dick's VALIS, which also blended Gnostic spirituality and sci-fi. This came back to bite the writers, as it's kind of necessary to understand the finale, especially the part about personal revelation (i.e. what meaning the characters and the audience bring to events) being more important than authorial dogma (the writers telling everyone what happened and shooting down all but one theory).
Babylon5 has Delenn of the Minbari, stating that "we are the universe made conscious, splitting itself apart to understand itself."
In Dark Alleys from Vajra Enterprises. In Dark Alleys has several philosophies in the history of unpopular ideas section. Animism, Buddhism, Platonism, Neoplatonism, Gnosticism, Descartian Skepticism, Sadism, Marxism, Nihilism, Freudian Psychoanalysis, Surrealism, Existentialism, Jungian Psychology, Punk, Paglian Feminism, and Postmodernism.
Aquaria is actually somewhat sympathetic to its Demiurge stand-in, Eric—he's desperately trying to recreate his unconditionally-loving mother. Although given that his most successful mimic turns against him, it may have been a fool's errand, and the Pleroma not even as noble as the Gnostics thought...
Final Fantasy VII had the Lifestream, which is the Pleroma in all but name, the Cetra, who represent Gnostics as opposed to the materialistic Judeo-Christian-ish humans, Sephiroth (whose name is from a Jewish Gnostic variant called the Kabbalah) as the demiurge, and Jenova as Sophia in her Alternative Character Interpretation of corrupter and destroyer of the world.
On the subject of Final Fantasy, Final Fantasy X had a more in-depth depiction of Gnosticism. The Pleroma is Zanarkand, and Sophia's fall from the Pleroma would be the destruction of the city, with Yu Yevon representing Sophia. Sin is the Demiurge: in the same way the Demiurge was created from Sophia's divine power, Sin was created from Yu Yevon's summoning talent. The Farplane also represents the Pleroma; everyone is made from the Pyreflies (divine sparks of light), and their soul returns to the Farplane after death. However, there are exceptions: anyone who died an unclean death, for example, will not stay in the Farplane and must be Sent there again. The Aeons also represent this, communicating with and helping humans from the Pleroma (Zanarkand) and fighting the Demiurge's influence. However, they can also represent Archons; in particular, Bahamut as Sabaoth, because they both turned against their masters in order to try and save humanity. The Yevon religion dislikes the idea that people can be free of Sin, and so they represent Christianity (in case it wasn't obvious enough already). At the end of the game, people are finally free from the influence of Sin, representing enlightenment and freedom from the Demiurge; but here it's a Bittersweet Ending, because this requires peoples' souls to fade away from this existence into another, meaning that The Hero Dies as he was from the Pleroma, the same way that the Aeons were.
The Mother in La-Mulana appears to be a pastiche of Sophia and the Demiurge. Like Sophia, she fell from the perfection of the heavens... although unlike her, she can't seem to get back on her own... and bears great understanding. Like the Demiurge, she created intelligent life expressly for her sake, namely to get her back up there—in a sense, to let her regain her glory. And every time, her children either turn against her, or extinguish themselves. Never mind that the fact that she fell to begin with might mean that re-ascension was impossible from the very beginning—just as, in the more severe forms of Gnosticism, the Demiurge has no ability (or right) to become genuinely divine. Nonetheless, this character is rather sympathetic— just being stuck on Earth is severely agonizing for her. She's not malevolent, but desperate.
Silent Hill— even the soundtrack lyrics have a Gnostic undertone. To clarify, Sophia would be Alessa/Heather, the human woman who created God and left it to the world, while the God herself would be the evil Demiurge, worshipped by misguided idiots. The story of God's creation also has Gnostic influences.
Xenogears is pretty much a straight retelling of it. [[spoiler:A good God (the Zohar) is pulled down from a higher dimension, and creates a woman from one of the sparks of light surrounding it (Elly). The Zohar is then used to create an evil god (Deus), which is followed by a false religion (-Ethos-), and while Deus created the world and rules it, using humans for its own purposes and letting its evil followers do whatever they like, the Zohar is the true, benevolent god.
Xenoblade—Though to a much lesser extent than its predecessors. The Monad(o) and Yaldabaoth are virtually the only references to it. Unless you look a little deeper, in which case Zanza is the Demiurge, who created the world in his image, with Meyneth serving as his Sophia, while Alvis is the real God, and the Monado represents personal truth/revelation, among other things. It doesn't name-drop as heavily as the previous Xeno-games, but it's just as Gnostic as them.