I was thinking of making my own "Isis's Heresy" idea were the Emperor made Daughters instead of Sons, Matriarchs instead of Primarchs. And, he made 12 instead of 20 (making it more like Jesus and his disciples). Thus, he has Femmarines (or 'Super Sluts') instead of Space Marines. This also causes sex to replace violence in this version of 40k. Sexual subjugation is used when possible. Though, many forms of Xenos need to be put down the old-fashioned way. In this version, the Emperor falls to his own libido and fuses with the Chaos God of Lust, Slaanesh. The Emperor is so powerful in this form the other gods of Chaos(Nurgle, God of Decay; Khorne, God of Slaughter; and Tzeentch, God of Change) are worried about their own survival. They seek out someone to throw their support behind, the Emperor's most powerful daughter: Isis. Instead of becoming Corrupt, however, Isis becomes the Goddess of Empathy.
The setting's origin is largely unchanged from pre-30k. The timelines start to diverge at the Primarch Project. The Emperor takes Malcador the Sigillite advice and makes daughters, not sons. This also prompted him to start the Grey Knight project earlier. Malcador didn't consider the Emperor's primitive sensibilities when it comes to women (the Emperor was raised during prehistory). The Emperor regarded his daughters and granddaughters almost like concubines. When he finds each for the first time, they are all so overwhelmed by meeting a being greater than themselves none refuse his advances; none, but the virgin Fulcrum. All of his Matriarchs have sexual relations with the Emperor (even Erinyes has hate-sex with him), except Fulcrum. Fulcrum the Pure and her legion, the Emperor's Daughters, remain cock teasing virgins until the Emperor's corruption.
The Emperor's unquenched avarice for one of his Daughters, Fulcrum the Pure, led him over the edge of madness. He bonded with the Chaos God of Lust to become "Emperor Slaanesh." Using his new powers he raped Fulcrum's legion of virgins with a penis-tentacle Warpstorm, shattering realspace itself and creating the Eye of Terror. While his Warpstorm raped reality, Emperor Slaanesh defiled his virgin daughter Fulcrum. This act changed Fulcrum the Pure into Fulcrum the Defiled and caused six of the Emperor's twelve Matriarch daughters to turn against him.
Emperor Slaanesh: Obsessed with fucking his Matriarchs and female space marines (Super Sluts), the Emperor merges with the Chaos God of Pleasure to make “Emperor Slaanesh.” His primary goal in doing so was to conquer the one Matriarch that never let him touch her: Fulcrum. Emperor Slaanesh's legion are the Grey Knights. Since they receive their gene seed from the Emperor himself, they are the only male Astartes in a universe full of female Astartes. The Grey Knights are hulking hunks and the purest representation of the Emperor's Lust. A squad of Slaanesh sorcerers who exist solely to rape the ever-living fuck out of the enemies of the Emperor with their massive, throbbing pillars of brotherhood.
Matriarchs Loyal to Emperor Slaanesh
Sanguiniura, Archangel of Slaanesh: The most beautiful and seductive of the Emperor’s loyal children. Fulcrum the Pure ever outshone the Archangel, driving her to unbound jealousy. Sanguiniura hated to be second in looks, and she hated Fulcrum’s unending quest for purity. The Archangel, of all her sisters, was the most overjoyed to hear of Fulcrum’s defilement. But, Sanguiniura’s envy remains unquenched as, even defiled, Fulcrum is the most comely of her sisters. Some even claim her beauty was enhanced by her encounter with Emperor Slaanesh. Voluptuous Sanguiniura has white-feathered wings and a taste for blood. Over indulging on wine and bodily fluids, she acts more like a succubus or vampire than the angelic form she embodies.
Rihanna Dawn of the Imperium of Fisting: Obsessed with large insertions, this champion of the Emperor Slaanesh uses her new Chaos powers to fill every hole passed the point of sanity. Their pussies ever under siege, the Imperium of Fisting isn't for the faint of heart (or inflexible of body). Her Femmarines Super Sluts regularly stretch their orifices, with the ultimate goal of fitting all of Emperor Slaanesh’s impossible tool into themselves. Since he can now make it the size of a starship, they often willingly die in the attempt. It is rumored that Rihanna was given the power to take all of him, however. And, with the power of Chaos, they say she has done just that.
Leela Ruby, the Wolf of Slaanesh: Leela Ruby and her Super Sluts are absolute savages in bed. They will fuck anything that moves as hard as they can and as often as they can. The Wolves of Space descend on unsuspecting worlds and bang the inhabitants into submission. Totally insatiable, Leela holds unending orgies on her Battle Barge the Ruby Spear. Leela makes copious use of Venus’s tools. She can easily wear out even her sister's perfected crafts, Plasteel grinding away on her insatiable clit.
Venus, Toolmaker of Slaanesh: Infatuated with making “the perfect weapon” dark-skinned Venus embodies the obsessive nature of Slaanesh. She crafts perfect vibartors and other sexual weapons to be wielded by the rest of the Femmarines. Largely unaffected by the corruption of Chaos (due to her obsession with physical crafts) she labors away. Venus designed ecstasguns that give orgasms over distances and chain-dildoes for hand-to-hand sexual combat. Her ultimate goal is to make an object as powerful as the Emperor’s own prodigious tool. One that could subjugate star systems and bring whole worlds to their knees in sexual ecstasy.
Lioness Jonson: A blonde bombshell of sexual power, this knight of Slaanesh is a master of tactics. She will belittle you even as she breaks through your defenses. No stranger to a sexual siege, the only thing in the Milky Way she was unable to conquer was Fulcrum. Not even the Lioness’s Femme Fatale charms could break through Fulcrum’s quest for purity. During their brief courting, Fulcrum practiced orgasim denial on the Lioness, leading her down the dark path to her corruption by the Emperor.
Robin Gillian: The only one to remain loyal to the Emperor AND remain uncorrupted by Chaos. Brown haired Robin is a bookworm of a 10-foot-tall supermodel. She wears glasses and is very easy going. Willing to go along with almost anything without protest, her peers feel she is too boring to be corrupted by Chaos. Still, to remain without the taint of the Warp while working for Emperor Slaanesh is a feat only someone as intelligent as Robin could've pulled off.
The Matriarchs in Rebellion
Isis of Lunar, Chosen of Chaos Divided: When Emperor Slaanesh raped Fulcrum and the Emperor’s Daughters in an all-out Warp attack that created the Eye of Terror, Isis knew she needed to save the galaxy before it was drowned in her father’s all-consuming lust. Her sister Loretta explained how Isis could use the other Gods of Chaos to stop their father. Thus, when Nurgle, Khorne, and Tzeentch tried to recruit Isis, they got more than they bargained for. In their desperation to survive, the Gods of Chaos Divided gave Isis too much. She was able to remain largely uncorrupted AND absorbed most of their power. Isis is now a beacon of light others are drawn to. She is everything her father could have been. Her powers come from the emotions of all living things, making her a nurturing Goddess of Empathy, much to the dismay of the entities whose power she stole.
Erinyes, Avatar of Khorne: The remains of Khorne’s power was given to Erinyes by Isis. This unfortunate Matriarch was raised as slave on a gladiator planet and had “the Butcher’s Nails” installed in her skull. The Nails made her a rage monster in combat and put her in a permanent bad mood. Even before Chaos changed the Imperium forever, Erinyes hated the Emperor. She hated him for every reason a daughter could hate a father. Thus, Erinyes jumped at the chance to become Isis’s Champion of Anger. The Nails still dig deep in her augmented skull, killing her even while empowering her.
Magda Firehaired, Avatar of Tzeentch: Magda was a powerful sorceress and understood the mysteries of the Warp before any of her sisters. Tragically, her first dabbling unleashed a plague of mutations throughout her legion. These unchecked mutations would have destroyed her daughters if not for the help of Isis’s new-found Chaos powers. Together they healed the worst of the mutations. By absorbing the remains of Tzeentch, Magda was able to use the power of change to her daughters' benefit. Thus, all of Magda’s Femmarines are powerful shapechanging sorceresses. While Isis is the most powerful Matriarch, Fulcrum the prettiest, and Robin Gillian the smartest, Magda is the wisest. No one understands the powers of the Warp like she does. Some say her knowledge of its secrets outstrips even Emperor Slaanesh’s understanding.
Moribana, Avatar of Nurgle: Moribana’s scarred face is the most... ‘exotic’ of the Matriarchs. Her stoic demeanor (and asthmatic breathing apparatus) are born of her harsh homeworld of Barbarus. Not even Isis’s new found powers could health her damaged sisters lungs and face. But, Moribana did accept the gift of Nurgle’s remaining powers of decay. While she is Champaign of Corruption, Moribana remains indomitable and resolute. She opposes the Chaos of her father's unnatural hunger. Moribana and her Death Guard Daughters will fight to the bitter end against the Tide of Lust Emperor Slaanesh has unleashed.
Loretta, the Balance of Chaos: While Magda is the best of her sisters at uncovering the powers of the Warp, tattooed Loretta was the first to realize it contained gods. Loretta was originally the most loyal of the Emperor's Matriarchs. Holy Loretta felt it was the duty of the Femmarines to bring balance to Chaos, and she thought the Emperor was the embodiment of that balance. Her Word Barring legion brought the Religion of Balance to countless planets in the Emperor’s name. She sought to unify the disparate parts of Chaos to create a harmonious whole. When the Emperor bonded with Slaanesh, he destroyed any hope Loretta had of balance. Shaken to the core, Loretta was the one that first gave Isis the insight that would lead to her becoming the Champion of Chaos Divided. It was Loretta’s guidance that let Isis control her powers and get the best of the remaining Gods of Chaos.
Fulcrum the Defiled: Before the Emperor was corrupted, Fulcrum the Pure was unquestioningly his most beautiful daughter. It is said this is even more true now. Lithe and supple, Fulcrum the Pure was physical perfection made manifest. She was also determined to remain a virgin. Fulcrum’s legion was named ‘the Emperor’s Daughters’ in a seeming reminder that they were the one group of Femmarines that would not have sex with the Emperor (or anyone else). Yet, Fulcrum and her daughters remained the most provocative of cockteasers. Masters of dance, they would flaunt their femininity and drive all that saw them mad with unfulfilled lust. They were also masters of orgasm denial, which was their chosen method of subjugation. Worlds were brought low in a heightened state of sexual arousal by the Emperor's Daughters and their ability to prevent anyone from cumming. It is said that the Emperor was masturbating to a holoimage of Fulcrum when he fully bonded with Slaanesh. This would explain why his first act was to send a tentacle-penis storm through the Warp to defile all of the Emperor’s Daughters stationed on their homeworld. He also personally teleported to Fulcrum and defiled her in every way imaginable. Fulcrum the Defiled is still the epitome of feminine beautiful, but -understandably- she has yet to come to terms with what was done to her.
Fulcrum still refuses to have sex, and she would sell her soul to reclaim her virginity.
(Please let me know if you like this idea and want me to write more in this setting. And, you can write in it yourself if you'd like. I would like it if you did, in fact.)