As much as I’d like to think there isn’t some similarity in how I’ve included peripheral P/pagan elements in fanfic lately, I think there’s the possibility.
“Kai” is an example of where I very clearly look like I rifled through the pockets of some pagan spaces and Wiki pages to form deities because it’s currently the only one where known names are used and there’s a clear priest(ess) and laity divide. Quite literally, there are temples, groves, hofs, etc. where religious people handle the communal shrine keeping, organizing rites, offering xyz services as part of their sacred duties, and offering a variety of divination related services, and then there are people who are semi-agnostic but fulfill the basic requirements for the deity’s patronage. (The details vary, but even when someone’s getting divination and a particular cathartic rite done, it’s very ‘live and let live’ on what they believe as long as they’re respectful.)
“Darkling” is a few steps removed from that because the clergy and religious components aren’t as widespread. The Dark community has experienced peaceful co-religious blending, being forced to new areas where assimilating into that place’s majority religion was inevitable after centuries, and in some instances, forced or faux conversions (as Christianization has been interpreted as one component of some Light communities).
This means that ‘the Ancients’ and the residual pagan flavors in certain holidays feel more like folkloric customs (an expression of culture rather than religious belief), and this allows for different levels of interfaith Dark communities from one country to another. The characters who are the main points of reference for the Dark community in the story take a stance where the Ancients are conceptualizations of magical forces more so than deities they ought to hold certain beliefs about.
“BSL” and “Coven” more or less share a Universe where the differences lie in when and how Harry is introduced to this toned down iteration of the Dark/Grey/Light divide (hard of hearing!Sirius post-PoA vs ‘curse damage as chronic pain’ post-war). Honestly, I wanted to make magical equivalents to wheelchairs based on clouds, and this whole disability, chronic illness, and chronic pain element showed up (magical accessibility aids, spell-signing, we don’t have space for my spell stuff). The coven structure that includes inter-pantheon religious stuff actually isn’t quite as prominent (in the plot and what I’ve worked out in the notes).
In “Coven”, Harry’s exposure has more to do with seeking out a means of mourning and catharsis that’s lacking in the Light community. Like, religion is kind of there, fictionalized titles are used instead of deity names, and some people believe, but it’s mostly a coping mechanism during grief (in part, because Dark folks have a community-wide recognized rite, support roles, and reintegration timeline that recognizes mourning while supporting the mourner).
“Kintsugi” is a little different in that the plot and Universe have to accommodate this underground, international, consensual D/s system. While I was thinking about how some people combine Pagan beliefs and BDSM, I didn’t really want to get into the particulars that might lead to ‘but why did you use my deity?’ conversations where the point of having divine support for D/s roles and rituals could get lost. So, I made a specific point of fictional tweaking to the two main deities for this system, so that readers hopefully wouldn’t focus too much on who the deities were and would pay attention to how they help a new power dynamic pair.
The inter-pantheon home practices are dependent more on familial lineages, change from one generation to another, and can have a variety of other deities (who may be more recognizable), but this winds up being very ‘home and hearth’ focused rather than the community element from other fics shining through. (It may feel familiar to people used to being solitaries with home focused practices.)
Ultimately, between all of these fics, there’s not really a sense that someone ought to hold a certain belief system or that it’s better for them to personally believe in these pagan-ish deities. It’s more that engaging in certain rituals, which may be communal or solitary, can be cathartic or otherwise beneficial to the individual. If we really delve into whether a deity exists, there’s some sort of transactional and/or reciprocal element (human does A and deity does B because it’s an arrangement). In more than one, the community aspect comes through because of grieving and mourning processes (seeing as how I’m writing HP fic, this isn’t just because I’ve got opinions on how people do or do not turn to religious communities while grieving something).
It doesn’t feel unrealistic, but it also does have moments where I worry it’s a touch impersonal. Even in scenes where there’s near death experiences and interaction with a deity in some way (rites, divination, etc.), the deities sort of just exist. The main characters whose points of view are telling the story aren’t the ones who necessarily have to believe in the deities, often don’t have solitary rites or devotional activities, and often don’t have personal connections with the deities. Other people are the ones doing the divination, starting and maintaining the shrines, planning the rites, and so on.