In my new setting I'm working on, I'm trying hard to not fall into the fantasy trapping of either having one mega-church that's evil and controls everything (WH40k, Ravnica), or a bunch of smaller ones that are so similar that no one cares about the difference (Forgotten Realms). I'm working on a middle ground where the gods are divided into smaller pantheons, each having their own church, but I'm still struggling to make the four churches distinct, how they influence society, and how worship of individual gods work

The four pantheons are (working titles) Pantheon of Duty (gods of combat and service), Pantheon of Knowledge (Vecna, god of secrets, Raven Queen, goddess of memory, and an unnamed god of learning), Pantheon of the Earth and Heavens (gods of nature) and the Pantheon of Labor (gods of work and labor). There are also four gods who, for one reason or another, are not included in one of the pantheons, so I'm not sure how worship of them would work. Some of them are major gods, so it'd be weird if they didn't have a church

maybe they don't have temples but they do have numerous shrines depicting them and their symbols, with a small dish/brazier for appropriate offerings. Additionally, fountains, government buildings, and all forms of art are a great way to depict those kinds of gods. Just think of how many devout christians pepper their office rooms and houses with crosses.

I like this idea.

I've been playing around with the idea of a having polytheistic Clerics be the norm, where a Cleric needs to invoke a Deity with a particular portfolio to make any Divine casting work ( and thus make Clerics something fundamentally other than Wizards ), but any Cleric has access to multiple Deities.

I've been thinking of having multiple Religions, each with a particular ideology and agenda, and thus a propensity toward the veneration of certain Deities, but the Deities might not be unique to that Religion. This wouldn't even require the Deities venerated by a Religion to be thematically similar, or even compatible - just useful to actions and values which are promoted and valued by the Religion in question. It would also allow for Deities of varying power and domain to be venerated by a Religion. You could have Deities with major portfolios ( Storms, Death, Nature ), and minor Deities with extremely minor portfolios ( I'm think of Janus, the Roman God of beginnings, gates, transitions, time, duality, doorways, passages, and endings ). Both types of Deities could be invoked, depending on the magic being wielded by a polytheistic Cleric, while having a Cleric solely devoted to a Goddess of Hearths seems unlikely.

This kind of make the Deities only concerned with the immediate action being performed, but the overall goals of a Religion are chosen and enforced on a secular level. A God of the Underworld may be willing to grant the power to raise up Undead to any Cleric who knows the rites to invoke and propitiate him - but the Monks of the Sacred Flame may-or-may-not dispatch an Inquisitor to look into the actions of one of their members who raised the Undead, depending on what the purpose of their creation was, and what the Ethos and beliefs that the Monks of the Sacred Flame espouse.

This allows you to have multiple, medium-to-large Religions, which have a unique and memorable character ( and which are likely in some sort of ideological struggle ), while having a large selection of unique and interesting Deities of varying powers, which can be used to add a great deal of flavor the magic being wielded by polytheistic Clerics.

I'm sure there a issues I still need to consider, but I think it could lead to an interesting twist on the Cleric in the game.

Typically when a major god isn't part of a pantheon, they're a forgotten god or don't matter anyways. Consider real world pantheons, especially Shinto, where Izanami and Izanagi, while they are very major and very important, being the creators of the current pantheon, they kind of slipped into the background (though you can't necessarily blame them, seeing as to the fact that one's dead and the other is probably hiding from the dead one).

Yeah, the gods that aren't part of the pantheon are outsiders for very different reasons.

Iphigenia, goddess of war, is an outsider because none of the other gods want to be associated with her (except maybe Helm), since her domain is essentially all tragedy

Deneir, god of writing, literature and history, has been busy stopping the Ethereal Plane from consuming everything for several thousand years, so the other gods in the Pantheon of Knowledge kicked him for inactivity, and included Vecna instead.

Bahamut and Tiamat are the big ones, gods of Peace and Conquest respectively (Tiamat is actually the goddess of collecting, including harvest and hobbyist collecting, but greed and conquest are more marketable). They have no parts in the pantheons because they originated independent of the other gods, being created from the death of Io, instead of being created from the Dawn War. They're essentially a different breed of god, but still very major gods. Some worshippers may say they're in the Pantheon of Dragons, along with Io, but for all intents and purposes, they're independent deities

Well, when there's a single deity like that with a specific purpose, most of their clergy is closer to a cult or sect than an actual church, where they're devoted to that cause. They don't often have representation. Oh, and just a suggestion (you don't have to take it by any means, and it probably doesn't fit in with your current ideas), I would love to see Sardior represented a little more in Fifth edition D&D. Just in case you don't know, he was a deity of gem dragons from some previous editions, and was the neutral force in that whole cosmology (Tiamat evil, Bahamut good, etc.) His domains are Knowledge and Trickery if you're interested, and had a rather unique take on that whole knowledge style domain (his focus was more learning from experience and experimentation than study, and preferred that his clergy be more focused on useful knowledge than just knowing for the sake of knowing).

I think the best route you could take in fleshing them out and making them uniquely distinct would be to model different groups after different irl religions. 

Quote from CinciOmega >>

I think the best route you could take in fleshing them out and making them uniquely distinct would be to model different groups after different irl religions. 

This is a pretty common technique which is used for in-world cultures as well.

I'd do this if I had a stable group of Players I knew well, or if I restricted myself to ancient religions with few - if any - modern adherents. That's a good model for cultural emulation as well. I wouldn't do this for a table with a rotating roster of Players and one-shot adventures.

Since I'm neither a sociologist or a theologian, I can't guarantee I'd understand what I'm modelling or emulating to not piss off someone at the table who is a member a particular religion or culture.

I don’t think you need to worry about upsetting people. What you base things off of doesn’t need shared with anything. I have a fully custom pantheon in my setting. Truth is I didn’t make it for my players. I made it for myself. My players love the pantheon and are fully invested in it, however in this end I made it because I enjoy world building. 😆 

if your into world building, fleshing out a pantheon is a blast. Definitely takes a lot of work though. I would say it is a common technique. A lot of world building is basing the homebrew off irl elements and things that inspire you. There’s no right or wrong. 

here’s a link to my pantheon if anyone wants to check it out :) https://www.gmbinder.com/share/-LYRs1asPqk2Yxrs4g9I

I've admittedly only skimmed this topic, so I hope this isn't repeated.

One of the major things to make your "Religions" stand out from all others is the fact that the worshipers of these Dieties >Have Direct Contact With Their Gods!< 

This changes the act of Worship from a matter of Faith to one of Duty, the same as a Knight would give to his King or Lord. These are people who either pick one to follow or live lives in direct interaction with the domain or aspects the god(s) manage and they seek a mutifully benefical arrangement. The Worshiper wants good things in his life and to not be used as a new brick in the Wall of the Faithless when he dies and the diety needs worshipers to keep them impowered, do their works and (some of them at least) don't want people mashed into the Wall of the Faithless either.

Having Clerics, Paladins or anyone with the Acolyte Background get spoken to by Followers of both their dieties and those related to them at least semi-regularly. Especially people who rely on divine intervention during hard times (Farmers during droughts for instance) or those who near death who need reassurance that they will be called by their diety out of the City of the Dead.

As for the matter of Polytheism, that already exists. At least in Faerun. There are multiple Holy Orders that don't worship or follow one diety but instead follow a pair, trio, or a whole Domain. Followers of the Triad, for instance, worship Tyr, Torn and Isaamel (sp?). While Paladins often worship both Tyr and Helm as they are the most connected with a Paladin's duty. Not to mention there being Racial Gods, so a Dwarven Paladin, for isntance, would give worship to both the Dwarven God as well as Tyr and Helm in his duties.

If you want to spice up how people worship in their daily lives, here is a few suggestions:

• A farming village a little ways from the city keeps a small shrine to every Agricultural diety they know of all at once.
• A newlywed buys a statue to a god or goddess of fertility and/or family to try and become pregnant as quickly as possible.
• A theif kisses a talismen to the god of thieves for good luck before he slips into the shadows.
• A family that can't travel to a larger church keeps a small shrine in their personal home that they give offerings to.
• A township gears up to a massive festival to the gods for their good foutine and for continued blessings in the future.

The main thing to remember with each example is that NONE of these are done based on Faith. On giving up their own view of the worlds to put their belief in a metaphysical being that may or may not exist (trying to avoid a debate here) but are instead are giving their worship to a Being that the *vast majority* of the people know beyond a shadow of a doubt to exist and some have even SEEN them.

One thing you could do to make each Religion unique is to have the setting be similar (but not exact) to how devils in D&D function. The power of each deity is 100% dependant on how many people willingly follow that deity. Therefore each deity actively attempts to persuade others to follow them over the "other god". Each deity might offer something unique to its followers (access to a modified spell, to start with) to entice them over.

Weaker deities can grant access to lower levels of magic, but might team up with a stronger deities by offering them some of their own followers in return for the ability to grant stronger level magic to their followers. They might be restricted to smaller shrines or less impressive buildings of worship and could overtake stronger deities if they gain enough followers.

Stronger deities might give access to higher level magic, but might make stronger demands of their followers at the same time (mechanically, maybe spells take additional spell slots, or have a gold cost associated with them) as compensation for their " good will". They might have extravagant places of worship built for them.

Rituals and Precepts. If you want religions to feel different, you need to show them, maybe even if it doesn't advance the plot. Give the followers of a religion particular gestures, sayings, foods they will not eat, fasting periods or otherwise idiosyncratic behaviours. Maybe gods of the craftsmen won't use iron cutlery because iron is reserved only for works for labour. Maybe the warriors gather together and light a massive bonfire, drink and commit feats of strength. Maybe there is a day where everyone wears flowers and makes a procession around town and each part of the town has a ritual to symbolise the mythology of the diety?  Maybe the warriors hold up their pinky fingers (as the pinky is an important finger in controlling a sword) when making an oath.

Here, it's the little details that are important: the ones that can get swept up in the rush to adventure. It's not really about the grand picture of how many gods you have or how they are ordered. If you wanted to do that, give clerics different spell lists based on which deity they follow, mixing in mage spells where necessary. Gods aren't their religions. Gods are great and mostly unknowable beings. Religions are things built by people and designed to be knowable and practised.

Riffing off of Verenti's post: public festivals and observances. 

Give the Religions public spotlight time, in the general culture at large, by having public festivals. In most of the western world, everyone knows about Christmas, Easter, and - possibly to a lesser extent in Europe - Día de Muertos, and these at least have their roots in religious festivals, and are still highly religious in nature to some people.

It's hard to ignore a particular Religion in your world, when the city is shut down for a festival, religious ceremony, day of fasting, or a carnivale. This has an advantage in that its seldom restricted to only the adherents of the Religion: it's a general cultural expression.

It also gives a Religion a distinct character by the kinds of festivals or rituals that are part of that Religion ( see Verenti's post ) - so this not only throws the existence of a Religion into the cultural foreground, but emphasizes its unique nature.

I wouldn't give every religion in your world the equivalent of Christmas - there is only so much you can realistically disrupt a culture with festivals and holy days - but even small, public, observances, even if only practiced by a subset of your population, can have this effect - so I'd give every Religion some cultural spotlight time. How much would depend on the level of adherence to that religion in your in-game culture ( which could change from region to region ).

Religions can be distinguished by grooming and clothing. In our world we have instantly-identifiable items like a Sikh's turban or a Buddhist monk's saffron robes. Adding little descriptions in to some of the NPCs will make the religions more distinct, as well as emphasise the message that religions are important in the gameworld.

"The innkeeper has the left side of his head shaved, indicating his adherence to the faith of Pelor."

"The guard is wearing an orange scarf over her armour, showing her support for the church of Lathander>

Small observances can also distinguish the faiths. For each god in your gameworld's pantheon, come up with a one- or two-sentence description of a common observance. Better stil, get the players to do it - get them invested in the world.

"Worshippers of Boccob always have an unlit candle somewhere in their home or shop."

"Followers of Shaundakul always have a decorated fan hung on a wall."