The cults of Pazuzu

Types of cults
There are three types of cults of Pazuzu:

The Autodestructive Cycle
Autodestructive Cults of Pazuzu are started when someone in desperate need discovers Pazuzu's name and pleads for his help. When someone utters the name "Pazuzu" three consecutive times, the demon lord is telepathically linked to that person for one minute. During that time, Pazuzu is capable of reading the thoughts of whoever he is linked to, in addition to checking whether they are lawful or good. After confirming that whoever said his name isn't endeavoring to capture him on the Material Plane, Pazuzu may appear before the speaker or send a representative in the form of a bird. Pazuzu grants the person aid, usually via his wish spell-like ability, or by forging a warlock pact, and in reply asks that his name be repeated to others. The mortal's miraculous turn of fortune attracts other desperate souls. Pazuzu continues to grant aid when called upon, each time producing more evil results. Eventually the cultists come to depend on him for their success, at which point he reveals his true nature. Those who try to repent are tortured and sacrificed. After a cult has committed its first sacrifice, Pazuzu abandons it and seeks out other prospects. Eventually the cult is destroyed by lawful and good forces; looters discover Pazuzu's name and the cycle's continuance is assured. These autodestructive cults are most commonly employed in places where Pazuzu has no hope of retaining lasting power, and only wishes to lash out at the common order. They are especially common among upper classes of highly ordered societies.

The Plague Killer
In places where Pazuzu can hold long-term sway, but is unable to dominate the society completely, he presents himself as a weapon to fight off evil and plagues, essentially "the devil you know." When a plague or other demon threatens one of these societies, they call on Pazuzu and make sacrifices to him to bring about his destruction, usually in the form of a swarm or infestation of birds. For example, in response to a plague of locusts, Pazuzu may flood the area with a massive flock of sparrows that will protect the crops and kill the locusts. In return, he will take the souls of any who eat of those crops and turn them into harpies in Pazunia.

He may make similar deals on smaller scales with individuals. For example, in exchange for the exorcism of another demon from a farmer's daughter, he may impregnate the farmer's wife with a harpy egg which they are to hatch and protect until the harpy can make its own way in the wild.

The evil of Pazuzu is always somewhat reasonable to those who join his long-term cults, and he does not turn his back on them or twist their desires. Instead, he helps only those who already have twisted worldviews and desires to begin with, especially selfishness and filth.

The Four Winged God
Some cults do not know Pazuzu's demon name, and do not summon him through those means. They only know him as the primordial god of birds and avian intelligence. These cults construct ceremonies for him, and reach out using warlocks to earn his favour and power, especially that of flight, controlling birds, and killing demons. They believe that the reason evil minded people are closer to the god is that killing the demons requires your soul to be dark to begin with, so they tollerate much from shamans of the Four Winged God.

The Cult of Harpies [Bybnus]
When a woman faces the destruction of her family to plague, some other women may whisper what they have heard from others... a long a secretive lineage of whispers of a name of a god that can help them. This begins the journey of the women to uncover this secret god who can help. In quite places, during the day, while the men are away, the women gather and repeat the name of Pazuzu. Their children are protected from the plague. Their men recover. But soon another evil befalls them. They gather to chant and swear off eating birds. The evil abates. They hang black crows feathers in their homes for protection. Some of them learn the language of birds. After several years, these women see themselves rightfully so as more powerful than the local priests. Their avian spies reveal to them the treachery and evils of the corrupt temples. They seek the power of vengeance, and eventually come to learn of the ritual to give them the power to protect their children forevermore. The grandmothers of this cult gather on a cliff, tarring and feathering their heads and throwing the children of corrupt priests from the cliff. Thus Pazuzu leaves them as the head priests of the larger temples are brought to bear against these atrocities. But they can never flush out every single child who heard that name whispered to her in her crib at night. And so inevitably the cult resurfaces a few decades later.

The Father of Birds on Demon's Chimney [Yunai]
The Yunai people believe that the Father of Birds, a massive black bird whose wings cover the sky, lives atop Demon's Chimney. Their cult is constructed from the social memory of a large black roc that used to roost there, and the fact that there is a portal to Pazunia there. The tribes that camp near Demon's Chimney respect the Father of Birds, and venerate him, sometimes calling on him to stop diseases or kill evil creatures lurking near the camp. However, they understand that the dark rituals of the Father of Birds use evil to destroy evil, so they only use them as a last resort. These rituals include the entire tribe releasing all captured fowl and swearing off eating birds for a year (or even their entire lives), a ritual scaling of the Demon's Chimney by a hero, the creation and wearing of feather headdresses or wings, the construction of elaborate patterns of roosts (poles crossed like a teepee without a cover to give a place for large birds to nest), leaving the dead out to be eaten by vultures, and even in extreme circumstances, the tarring and feathering of one of their tribesmen (a human sacrifice). In rare cases, this tarring and feathering leads to the transformation of the tribesperson into a harpy, which can then either heal the disease, end the plague, or kill the target beast. The area around Demon's Chimeny also sees many lonewalkers who are warlocks of the Father of Birds, often sought out when these rituals must be performed, but otherwise considered pariahs.