A post about some of the lesser known Chaos gods inspired me to do this. The fluff has stated that there are many other, lesser gods besides the big 4. This makes a lot of sense, because Chaos gods are created by emotion, and not every emotion is covered by the spectrums of rage/pride, love/lust, despair/acceptance, and hope/ambition. So what I wanted to do was start a thread for people to make their very own minor Chaos god.
Your god's sphere of influence should be distinct enough that you're not just cribbing from one of the big 4. I think the main thing that separates a really weak god from a really strong daemon is that the gods are independent entities. They formed on their own in the warp from people's emotions. Daemons, on the other hand, are created by other gods, who have complete power over them. Even Be'lakor, who started out as a mortal and was exalted by all the gods, only has an illusion of free will.
http://wh40k.lexicanum.com/wiki/Be%27lakor
Here's my idea for a minor god. I'll cover the the god's appearance, sphere of influence, gifts, cults, and relationship with the big 4.
Cyl, the Jealous God
"It is not enough to succeed, others must fail."- Gore Vidal
Cyl is a minor Chaos god whose realm is Envy. Above all else, Cyl embodies the hateful, obsessive desire to possess what belongs to another. Unlike Tzeentch, Khorne, and Nurgle, who are typically viewed as male, and Slaanesh who is viewed as hermaphroditic, Cyl is most commonly viewed as a female diety. Cyl takes the form of a hunched, withered old crone, bitter and twisted from long years of want. Her thin, greasy white spills from the top of her head down the the ground below her where it lies in matted heaps. Her skin is pallid, grey, and cold like a corpse. Her teeth are blackened and rotten, and where her eyes should be there are only empty sockets with endless, blackened pits within. Her arms and fingers are unnaturally long and thin, and end in sharp, dagger-like nails. She uses these nails to rake out the eyes of those who displease her. They are said to be sharper than the strongest power blade, and able to rip the very soul from her victims' bodies.
Mark of Cyl- While some gods reserve their mark for those who prove themselves worthy, Cyl marks all her followers freely, indeed, obsessively, as soon as they begin to toy with enlisting her services.The Mark of Cyl may cause physical mutations to manifest. Grey skin, body temperatures that are constantly feverish or unnaturally cold, and eyes changing to a yellow or unnaturally bright green color are the most common mutations. However, the main effects of the mark are mental. Even mild jealousies will grow into hateful fixations in those under the influence of Cyl. A person marked by Cyl may also develop sudden talents for torture, either physical or psychological, and will often show signs of sociopathy and pathological lying. For one marked by Cyl, simply possessing the object of their desire will no longer be enough. Such a person will want to see the desired object's previous owner completely destroyed, ruined, and possibly killed, but only after a great deal of suffering. Once a follower of Cyl has taken what they want, they will inevitably turn a jealous eye towards someone else. They can never be satisfied.
If someone with the Mark of Cyl attempts to turn away from the god, they will immediately suffer horrific consequences. They may suddenly come down with uncontrollable vomiting and diarrhea, which will not stop until the victim has succumbed to the effects of dehydration and starvation. Their organs may begin to swell until they burst forth from their bodies. There are a multitude of ways that death awaits for those who turn their backs on Cyl, for Cyl is indeed a jealous god, who will not tolerate another being placed before her. The only thing that may save a former Cyl worshiper is the intervention of another god.
Cults of Cyl- Those who worship Cyl hope that she will help them obtain what another has. Her followers could include a politician or businessman brought low by a rival's success, a noble woman eyeing another's husband, or an impoverished wretch looking at the hab blocks of wealthier residents with an envious eye. Followers of Cyl are more often than not, lone madmen and madwomen. Jealousy is, after all, usually a personal affair. When Cults of Cyl do crop up, they tend to be among dispossessed classes of people, turning an angry eye on the larger society that has marginalized them. Cults of Cyl are usually highly unstable, filled with internal conflict, and often murder their own leaders, making it very difficult for them gain any kind of real, lasting, widespread power.
Probably the most infamous Cyl cult is the Brotherhood of Hungry Dogs, which led an uprising on the hive world of Beradir V. The Brotherhood arose among the mutants living in the underhive, but when food shortages caused a famine throughout the hives, the Brotherhood began to spread like wildfire among factory workers. Members of the Brotherhood would kidnap members of groups higher in social status than themselves, such as merchants and enforcers, and hold secret meetings where they cannibalized the captives while they still lived. However, the true target of their hate, the nobles of the Spire, remained out of reach. When the cult finally grew enough and had stockpiled enough weapons, an army of tens of thousands mobbed and ransacked the Spire. The rebellion was crushed by the PDF and the Adeptus Arbites, and a brutal purge by the Inquisition followed, but by the time the Spire was retaken, half the nobles had been slaughtered, and most of the rest were left horribly maimed and mutilated.
Relationship with Other Chaos Gods- Cyl hates all other gods in general, and anyone and anything that people might worship instead of her. She hates the four most powerful Chaos gods especially, because they offer things to people that she cannot, and take from her pool of potential worshipers, keeping her weak and her number of followers relatively small.
Khorne- Khorne offers a swifter, bloodier retribution than Cyl can. He gives his worshipers a chance for a much more immediate revenge and release. Cyl views a quick slaughter as too good for those she is envious of and would rather mull endlessly, letting the bitterness and hatred grow. She hates Khorne for the many, many times mortals have turned to him rather than her. Khorne views Cyl as weak and ineffectual, and despises her.
Tzeentch- Tzeentch offers a brighter looking and more potentially rewarding path than Cyl for those who are looking to obtain their hearts' desires and are less concerned with harming others who possess what they do not. Tzeentch has easily made use of followers of Cyl, either directly turning them to him when they are useful, or manipulating them into being unwitting tools. Cyl loathes Tzeentch's manipulation and will try to spitefully thwart his plans if able, while Tzeentch views Cyl coldly and dispassionately as another potential tool in his aresenal.
Nurgle- Although Nurgle's realm doesn't directly encroach on Cyl's, he views her as something of a joke, and will often seek to infuriate her for his own amusement. Typically this involves saving a former follower of Cyl who is on death's door due to the Mark of Cyl, and turning that follower into a champion of Nurgle.
Slaanesh- Slaanesh represents everything Cyl lacks and hates, particularly wealth, popularity, and beauty. Because of this, Cyl will go out of her way to attack Slaaneshi daemons and worshippers and ruin their plans. She is not terribly effective at this, since her own worshipers are often less advantaged, talented, desirable, and powerful. Slaanesh views Cyl with open contempt and treats her with cruel annoyance when they cross paths.
That's my minor Chaos god. Pleas elet me know what you think, and if you have any ideas for your own gods, please post them and I'll give you my feedback as well.