(T>B) Magic theory 201

From this thread: https://www.fimfiction.net/group/50/the-writers-group/thread/463514/magic-mechanics

Basics of Magic

Magic is a quasi-fundamental force - equal to the four that define the universe, but not necessary to existence as we know it like they are. So it's presence can distort and disrupt them - bend the laws of reality, sometimes to near breaking. It's also associated with life and thought - indeed, it's influence might be the source of such odd phenomena to begin with.

In some places, like Earth, magic runs nigh-undetectably thin. But in others, like Equestria, it's denser - perhaps it's to do with a fluke of it's core, or the region of space, or just a coincidence. And a great number of the lifeforms and substances found on that world will be imbued with or modified by it's presence to some degree - kind of like radiation, but usually more benign (because it responds to the subconcious wishes of those who imbibe it). Some of these creatures may eventually develop ways of tapping into magic (their own or external) and manipulating it for various purposes, while others settle for learning magical "recipes" that can make use of it's power "blindly". And then there are spirits, which are (mostly) formed of magic itself - some say all creatures carry one of these, a "soul", inside their physical body.

Moving from broad theory to the world of the show... magic isn't quite everywhere, but it is anywhere. Many races possess it to a greater or lesser degree, with ponies on the "greater" end - but several other races have it too, as do some animals and monsters, and plants... strange places, as well, where miraculous or horrifying things can happen. Pony scholars have catalouged and studied a great deal of the more reliable magics, but there are always more things out there for explorers to find. (Although for every real one, there are half a dozen pure myths.)

Pony Magic
So what magic do ponies, in particular, have? Well, a lot - it's literally imbued into every cell in their body, their organs being able to both absorb it from environmental traces and process it from food. (So recovery of expended power depends on the magic level of the environment as well as the available diet.) This passive magic confers on ponies a number of benefits they very rarely think about, from passive buffering of their internal organs (slam them into a cliff and you might break their bones, but not their spleen) to an accelerated healing rate (said bones will probably be fine in a week or two, and the bruising will be gone within a day or so).

Pony magic especially gathers in their keratinous parts - their hooves (allowing a "magnetic" grip and, with training, manipulation to almost match human fingers), their manes and tails (allowing some ponies to control them like extra limbs, an art called cappilurgy) and their coats (given them their signature bright colours, as well as allowing the most powerful and mysterious universal pony magic, the cutie mark).

Of the individual tribes, earthpony magic is the most subtle, and possibly varies depending on the ground they're raised in (Still working that part out). The most common variant is what some call the "Cornucopia Effect", where their magic flows out of them into the ground increasing it's fertility and encouraging plant growth. (It can also be used more actively, to create botanical miracles - most earthpony towns will have at least one public structure built into a specially-grown tree, and in some places it's even the common method.) While unbelievably useful (a human could count the number of famines in all Equestrian history on their hands), this power does have a cost - land that becomes used to it will be utterly unworkable without magic afterwards for several times the length of exposure, no matter it's prior quality.

The above power does tend to overshadow other earthpony powers, but they do exist - for instance, there are those whose affinity is to rocks instead, being able to shape and cultivate them. And several sorts of magic not innately particular to any tribe are most represented among the earthponies, be it trained skills like capillurgy or individual talents like beastspeakers. (That the most talented beastspeaker in modern Equestria is a pegasus is considered something of an embarrassment, which is one reason it took her a long time to be officially acknowledged as such.)

Speaking of pegasi, their innate magics are probably the most straightforward and consistent of the three. Clouds are solid to them (modern Equestrian ones have enough of their magic to support the weight of most birds too),but mouldable, like clay - the same power let's them shape other weather, to a degree. And the magic they channel through their wings and body lifts them off the ground and propels them in an almost reactionless fashion, even extending to "float" objects attached to them.

And as for the most flashy and famous, unicorn magic... for most unicorns, it's almost as instinctive as pegasus flight. Both telekinesis and one's talent magic - you can push it, train it, but it'll only improve so far. (Powerful emotions can help, but are also risky.) Actually learning a spell... well, it's kind of like trying to learn a musical instrument, higher maths and a foreign language all at once. So it's pretty uncommon (though not unheard of) outside of "magic talents". So the range of unicorn abilities is quite eclectic.

One thing unicorn magic is actually quite bad at having a lasting effect on, though, is ponies. Oh, there are all sorts of spells which can temporarily transform or otherwise affect them - but their own innate magic will rub against the enchantment and eventually erode it. This is one reason magic for healing others is quite rare among unicorns (almost as much as magic for seeing the future) - wounds transfigured closed will reopen, limbs regrown will dissolve. This "disruptive resonance" is why it is also very difficult for unicorns to combine their powers in order to cast magic greater than they can alone.

Do you have a set of rules that differ from few instances of the show?

Here and there - my unicorns can't cast at an object totally blocked from them (like inside a box or on the other side of a closed door) for instance, which I think has been done once or twice in the show. And there's no ban on mane magic.

What are its limitations? Most dangerous spells, and are there any underlying side effects?

Well, I list a few above, such as targeting and impermanence (especially on ponies). In the end, a lot of limitations are personal - a pony can only raise their power so high, or stretch their talent so wide. And while strong emotion can sometimes break those limits, such an exertion is very rarely without consequence - even if you don't kill yourself or burn out your magic, you might attract forces you really don't want to.

Strongest magic users?

Well, strength isn't everything. The magic of each pony tribe (especially the more active uses of it) rest on three "pillars" - power, talent, and experience. The first is key to even passive effects, and determines the scale of one's output (as well as boosting lifespan). The second helps define what uses of your power come easily to you, or are even possible in the first place. And the third lets the more limited push their power to it's limits, or find clever uses for it - and lets those few with nigh endless capacity improve their magic almost indefinitely.

So using unicorns as an example... Twilight, Sunset, Starlight and Star Swirl all have massive amounts of all three (though the nature of their experience varies). Trixie has high talent, middling power and is mostly self-taught. Sunburst has unusually low power, but ranks high in both other areas. Shining Armour has almost as much power as his sister, but a relatively narrow talent (he's also one of the few ponies to learn some spells outside it, as the guard teaches several basic useful ones to anypony who can). And Season 1 Rarity, with no more than slightly above average power, high telekinetic dexterity and a small but beautiful repertoire of spells, represents about as good as you can get with a "normal" talent and no formal magical training.