Magic
Okay, I feel like I should probably explain a little bit about how magic works in The Ceridwen Collection, even if it doesn't show up in the main works. I know that, in canon, it's sort of implied to be a hard system, there are rules and laws about magic, and it's been boiled down into a researchable thing. And some fics take that further, adding in magical cores and the like. From a meta-view, it's very soft, things happen and we don't get to know why. From what I've seen, the former seems to be more popular. It's also not the one I'm going with. Neither is the latter.
An important piece of context here is that I'm an occultist. Magic is literally what I study. The thought that leads to magical practices, the practices themselves, the philosophy explaining it. It's my bread and butter, why I throw in little tidbits of magical worldbuilding in The Monster Club. So, the one thing that I keep in mind with magic, and that you might not know if you aren't an occultist is:
Magic defies definition.
And I don't mean that you can't define aspects of magic, because you can, technically. What I mean is that magic, as a whole does not let itself have concrete rules applied to it. It escapes any singular definition you might try and use to regulate it. That probably sounds crazy, but I... I don't really know how to explain it if you haven't studied the occult and esoterica yourself, but it just does. Magic doesn't like being defined. And I think that it's partially because magical systems are, in part, systems of thought. And magical thinking varies by culture, and by person. An... an Ancient Egyptian wouldn't approach magic the way that a Theosophist would. The same rules wouldn't apply, because the practices, the magic would be so wildly different. So, knowing that magic isn't constrained to a universal idea, how do I approach it?
Well, I use my background in the occult, Folklore Studies, and Mythological Studies. I talk about it a little bit in my thesis, "Wizards and Religion: A Meta-Analysis" but something that's really common is magico-presentism. Projecting what we think magic is onto people in history. Which... isn't accurate? Magic was sort of inextricable from religion, at least for pre-Christian societies. But it also wasn't really magic, it was their religion.
And a key part of that is that magic was... more fluid, more symbolic than we as a society think about it today. Nowadays (kind of because of Harry Potter) magic tends to be thought of as waving a wand and making something float. But again, that's magico-presentism talking. Magic... I think the best way of describing it is that magic was more... poetically contractual? If you do these specific things, that have these specific symbolic meanings then you might have your desire granted.
It's not... it's not the best, nor is it the most accurate, but it works as an explanation. But we've kind of gotten sidetracked.
So, there are two Principles that I'm using as key pieces of magic, for the most part. The Principle of Sympathy, and the Principle of Contagion. The Principle of Sympathy is something that's really common in fantasy, even if it's never actually addressed. You might know it better as Sympathetic Magic. It's the idea that like affects like, a good example would be poppets, where the magician uses a doll as a stand-in for the target of the magical operation (also, no, poppets aren't tied to stuff like Vodou. Seriously voodoo dolls are just the socio-cultural brainworms that you were unaware of. It's just tacking on an African Diasporic Tradition to make it sound scary, a long practice in history. Little rant over.) The Principle of Contagion is actually kind of present in Harry Potter. It's the idea that, by handling something, it forms a metaphysical bond with you, allowing a magical operation practiced on it to affect you. Sort of the Scarcrux situation, where Harry has a link with Voldemort because of the contact. It almost always goes hand in hand with the Principle of Sympathy, because of the link sort of being Sympathetic.
Now, the PoS and PoC aren't really going to affect things like Thaumaturgy(Charms) or Transmogrification(Transfiguration) because I don't want to alter the canon magic too much, so those Principles are primarily going to be applied to the systems I add. But, that doesn't mean I'm not altering the core system at all. No, I'm using fairy tales as a base. Specifically, I'll use The Little Mermaid to illustrate my point. Yes, pause to laugh, I get how ridiculous that sounds. Anyway, fairy tales tended toward being darker (though a lot of the really gruesome ones are exclusive to the Brothers Grimm) and there are a few key rules about fairy tale magic. The first is Sacrifice. For example, in The Little Mermaid, the titular character has to sacrifice two things. The first, her ability to be a mermaid ever again. The second, her tongue, as payment, because all magic has a cost. The sea witch has to sacrifice some of her blood to make the potion that will let the little mermaid become a human.
In the tale, the little mermaid has to make the prince fall in love with her, his love has to be so deep as to make him
"[...] forget[s] his father and mother and cling[s] to you with all his thoughts and let[s] the priest place your hand in his hand so that you become husband and wife [...]"
If the little mermaid fails, she won't receive the immortal soul she desires and will die, turning into seafoam as the rest of her kind do upon death, at dawn's first light. That's a part that I won't be using, the grand sacrifice. Because, while there are small sacrifices, there's always the Grand Sacrifice.
The second key rule about fairy tale magic is the Loophole. There's always a way around the spell's limits, a way to get through the enchantments. In The Little Mermaid's case, the titular mermaid's sisters sacrifice their hair to the sea witch, gaining a knife in return. Having failed to fulfill the spell's requirements, the little mermaid is doomed to die, unless she uses the knife to murder the prince. His blood dripping on her feet will return her tail, allowing her to return to the ocean. A way through the magic, a means of breaking the spell. Ultimately, however, she doesn't murder the prince, throwing the blade into the sea. And revealing the third key rule of fairy tale magic.
The power of Self-Sacrifice. It might seem like an extension of Sacrifice, but they're distinct. Through sacrifice, the little mermaid is able to have spells cast. It's through Self-Sacrifice that magic occurs. By trying to do good deeds, and bring joy to the prince, by sacrificing herself instead of another, the little mermaid turns into a sylph, a daughter of the air. After 300 years (the lifespan of a mermaid, coincidentally) of doing good and spreading joy, the sylphs are given an immortal soul. It's through Self-Sacrifice that the little mermaid experiences natural magic, and its transformative power.
There are other key... Powers, we'll call them, in fairy tales. True love's tears, for example. In The Snow Queen, Gerda's tears are what cleanse the Devi's mirror shards from Kai. In Rapunzel, her tears heal the prince's ruined eyes. The tears of familial love in Cinderella grow a broken-off hazel branch into a full tree. It's in Cinderella that we see another of the key Powers, that being nature, and the manifestation of magic through family as represented by nature. In the original story, there is no fairy godmother. It's the hazel tree that was grown from the tears of Cinderella grieving her mother that provides her dress and shoes. It's the magic of Cinderella's promise to her mother that causes the animals to help her.
So, with all of that established, how does it affect Harry Potter magic? First, the Loophole. Every spell will have a means of circumventing it, even if it's obscure, or currently unknown. For example, Alohomora and Colloportus. One locks, the other unlocks. There's a way through the magic. When it comes to Sacrifice, call it cliche, but I'm going with a form of exhaustion. Not magical though because, as I established in "Bardic Magic vs Magician Magic", magicians draw from an ambient global field of magic called The Wellspring. No, it's usually mental exhaustion instead. Sort of just as a natural impact of having to remember the exact incantation, the wand movement, yada yada yada. But! The price doesn't have to be mental exhaustion, or paid by the caster. With Sacrifice, there's usually an element of the PoS or of a symbolic thing. The little mermaid would never be able to return to the ocean in return for life on the land. So, you have the price that has to be paid, but you don't want to pay it? Make someone (or something) else pay it. Take Diffindo as an example. You could pay in a bit of mental sharpness in the here and now, or the cost could be the destruction it deals. The breaking of its target, or the blood from a cut it inflicts. The key thing is that there is a price to the spell.
The final part is more for esoteric magic, like Lily's Protection. I get we, as a fandom, love making fun of the whole "love is the power" thing, and theorizing about how she might have used a ritual of some sort, hell, I've done that in The Monster Club, but I'm not doing that here. Love as a magically powerful force has precedence, at least in fairy tales. Combining that with the power of Self-Sacrifice gives us things like Lily's Protection. Which, as an aside, is the Loophole for the Killing Curse.
But let's examine a spell set through this lens, to give an idea about how this system meshes with canon. The Unforgivables. We'll even go with the order that Crouch!Moody uses. First up, the Imperius. Sacrifice and Loophole. What exactly is the Imperius? Well, a spell that, in essence, mind controls someone. Crucially, the spell is described as putting you into a feeling of bliss and happiness. And using the Imperius sacrifices that in you. Each time you cast the curse, you lose a piece of your ability to feel happiness, to be peaceful. The Loophole is... odd. They don't necessarily have to be magic, so you could argue the ability to resist it like Harry does is the Loophole. Maybe there's a magical Loophole, maybe there isn't. I've not decided.
The Cruciatus is, I feel, fairly clear. The Sacrifice is your own sanity. Bit by bit you start losing your grip on reality. The logic? Look at the Longbottoms. As for the Loophole... things are a touch complicated. You could go the route of having it be a potion to deal with the immediate after-effects like fanworks tend to do, or the Loophole might not have been discovered yet. Bellatrix is a strong argument against the Sacrifice I posit, seeing as (in canon) she's quite lucid and put together, but, you know what? I would argue that the whole torturing two people into catatonia is proof she's not all there.
The Killing Curse's Loophole is the Self-Sacrifice deal, of course. But, the Sacrifice? You lose a little bit of time from your lifespan. Each life you take, yours is that bit shorter. Maybe not by much per casting, but for people like Voldemort? That builds up over time.
As for classifications of magic, I'm largely planning on just referring to the traditions I actually implement. I'm getting rid of Dark Magic though. "Oh, but homo-" Nope, it's going. First of all, what the fuck even is it? You could argue for any definition because of how vague it is in canon. The vagueness isn't the core reason why, though. This may be a bit of a soapbox issue, so prepare.
The idea of "Dark" or "Black" magic that's inextricably evil is fundamentally rooted in racism. This isn't a JKR issue, to be clear. It's a sociocultural issue that's been hard-baked into the lens we use to view magic in the modern day. The idea that "Black" magic or "Dark" magic is evil is a direct byproduct of past generations vilifying and discriminating against black people. More specifically, it ties into slavery. Wild link, you might be thinking, but slaveowners didn't want their slaves to have any link back to their cultures of origin, so they did things like give them "Christian" names, things a "respectable" white person could say. But they also wanted to stop them from practicing their religions, because that was still a tether to their "barbarous, uncivilized" culture. So they started vilifying it, placing the "evil dark magic" as something to be stopped in comparison to the "good white Christianity", which eventually evolved into the idea of Black/Dark Magic and White Magic. Of course, they completely failed at trying to stamp out ATRs seeing as they're still a thing, as well as evolving into ADTs. But the point is, I cannot, in good conscience, write a system that is built on that dichotomy. Call it "SJW" behavior, or an issue that no one cares about, but I care. When ADTs like Vodou are still being used as the "evil spooky villain magic" I, personally, cannot find it in myself to perpetuate that belief. Seeing how ADTs are used as shorthand for villains in supernatural-based media is something I've grown up with my entire life. It's something that's taken for granted, even back home in South Africa. If I can help combat that, even just by having one person realize the issue, I'm going to do my part. So, yeah. I'm getting rid of Dark Magic and the Dark Arts as a whole. It might seem silly, but I won't compromise my beliefs even if it's something as insignificant as Harry Potter fanfiction.