I’ll try to extrapolate here how magic can be ingrained in a setting and have various moving parts to poke and prod in order to make it more interesting. Now, I won’t present a ready-made rigid system here, I’ll just be discussing paradigms and options for you to work into your own system or setting.
The Vancian Paradigm
What you’ll see in most games are spells you cast using some sort of magic juice. Some might use points, some spell slots, some magic dice. Effects of spells are better or worse defined by the rules (see Pathfinder or 3+ed. of D&D for very detailed spells) but their interactivity is rooted primarily in the system.
What I mean by this:
Spells boil down to “push a button to fireball”
Magic often lacks tangibility (fireballs don’t set things on fire, lightning doesn’t electrify water)
Lore doesn’t impact how you cast (limited interaction with your god as a cleric, etc.) and only very little of what you cast.
Lore in turn often fails to be impacted by casters able to fell entire armies at once.
Following on those points – the magic is woefully divorced from the world and no 20-page expositions on special magic juice in ley lines or midichlorians in your blood can rectify it if it doesn’t impact how your casters play.
The Organic Paradigm
Organic magic is one that’s deeply rooted in the world. It’s impacted by how the world works, by how metaphysical phenomena express themselves in it, and the world is impacted by it in kind. Naturally the place between what I’d call “vancian” and “organic” is a spectrum and not a binary.
What are the principles of “organic” magic?
Casting is involved, requiring you to do something specific in the fiction, like clothe yourself in crow feathers, spill your own blood or scream incantations to heaven.
Magic is tangible and operates on tangible things (fireballs set fire to things, lightning strikes travel across dirty water or metal, perhaps you need a source of fire and some fuel to conjure an actual fireball).
Lore impacts how and what you can cast.
Lore is impacted by magic, either filled with wizardly philosopher-kings, or having ways to counteract magic.
The more of those you have and to a greater degree, the more organic your magic is. Mind, though, that too involved casting may end up taking the spotlight away from other elements of your game.
Casting
Here are some ideas to make casting more involved:
Places, where you go to cast a spell.
Graveyards for necromancy, leylines for arcane magic, caves for earth magic, windy plains or mountains for air magic.
Items, what you use to cast a spell.
Mirrors or pictures for illusion, bones and skulls for necromancy, holy symbol pendants for divine magic, wands out of ancestral branches for druidcraftActions, what you do to cast a spell.
Drawing circles in the ground, spilling your own blood, screaming your demands to heaven, setting fire to your surroundings.
A lot of the time casting is self-contained, but you can expand it. For example, you can perform a ritual in a given location and bind the spell into an object, then release it later.
Sources
Let’s look at sources of magic that could make it more involved, or how to make the commonly used sources more involved.
Character, some internal capacity, them acting as a catalyst for cosmic powers, etc.
Exertion, quite common in fiction, the character could exhaust or injure themselves by channelling heavier magic. The player could choose to injure the character in order to invoke a stronger spell.
Emotions could influence casting. This is arguably not very interactive (you can say what your character feels any time), but interesting for flavour and roleplay.
A living thing, that means a god, a demon, or even a physical being that somehow can reach out through space to do something extraordinary for you.
Works, performing tasks, bringing their perfect world to life (spreading disease for plague god, or setting things on fire for a fire god), minding their laws in your day-to-day morality.
Relation, that is, making sacrifices to your god/demon, talking to them, learning more about their will and idea about the perfect world, performing rituals commemorating stories about them.
Factionalism, getting engaged in your god’s wars, furthering the cause of your priesthood or church, conquering land and proselytising.
Effects, deities of war would enhance your abilities in battle, deities of nature would grant you control over plants or beasts.
Similar to a living thing could be a metaphysical principle like Chaos. While it would be difficult to have a relationship with it, you could certainly enhance your magic by making your life chaotic, spreading chaos across the world or sacrificing things to it.
A physical object, either wrought into usable coherence like a wand or a sword, or raw material.
Tangibility, something you can hold in your hand, something that can be stolen from you or that you can steal, buy or find makes magic a bit more interactive.
History, the sword is magical because it slew a giant long ago, the armour is resistant to fire because its wearer withstood the dragon’s breath and survived.
Crafting, which adds a “fiddly” aspect to magic; either consider the alchemical implications of mixing phoenix feather and essence of earth, or simply pour “magic juice” on things and see what happens.
Availability, “magic juice” could be extracted out of blood of magic creatures, the sap of world trees and tears of the elves. It could perhaps be traded for or stolen, though more about it in the setting impact section.
Effects
Here are some ways that spell effects could be modified or affect the world beyond just fulfilling their function:
Tangibility, as mentioned before, the fireball is a real ball of fire that burns things and sets them aflame, lightning travels down metal, etc.
Corruption, similar to radioactive materials, poisoning water and land, mutating living beings, rusting metal and the like; requires special equipment to handle and clothing to avoid contamination.
This isn’t limited to radioactive-like corruption. Perhaps using nature magic makes nearby plants grow faster and spread, perhaps moon magic makes things nearby glow with fluorescence, etc.
There are systems out there that cover modifications to effects, like making them affect the caster or random targets and the like, so I won’t talk about them here.
Setting Impact
I’ll bring up only the guideposts for this, as magic’s impact on setting and vice-versa could be covered in its own post.
For many of the systems and worlds I’ve seen, the core questions that should’ve been asked were:
What is the counterplay to magic, a way to stop it or avoid it?
Why aren’t wizards running the society?
Why are there still armies if the wizards can wipe them out?
If magic is material, then acquiring and trading it could be the way to power for individuals and nations. Wars could be fought over it like over land or resources. Perhaps it’s banned or only available to higher echelons of society?
Let’s talk a little bit about counterplays to magic.
A material, like lead, could be impervious to magic, so a caster couldn’t wear it, but it’d be invaluable for a fighter; perhaps leaden weaponry can kill magical beings, ghosts or summoned creatures.
Volatility, if magic can kill or maim the user, then it’ll certainly make it less likely to be used and for wizards to become the ruling class. The counterpoint to this is that if it’s random, it might feel pretty awful to the player who gets turned into a frog for casting featherfall.
Divine limitations, so for example if two armies are at war, so are their gods, and either the battlefield is a storm of magical and physical violence, or the wizards can do little more than chant on opposite ends of the battlefield. Likewise perhaps the deity or demon granting magic is fickle, tires quickly, or their power is limited (or it’s scared of dogs).
To summarise, an organic magic system is one that has many moving parts in the setting and not necessarily in the system that can be interacted with. This is by no means an exhaustive work on the topic, but I hope it helps set a new direction of growth for magic systems on the whole.
Interesting pieces to check out:
Sorcerer by Ron Edwards, a game about utilising and managing demons.
Ars Magica has a pretty complex and clever magic system that’s certainly worth checking out.
There are a sleugh of OSR systems and blog posts that cover magic, the GLOG wizards by Goblin Punch is especially of note.
This list could be significantly longer, I’m sure you’ll find more interesting reading material out there.
