The Metaphysics of Magic Items
Every individual has channels of energy which flow through them, which collect, pool, and travel along lines which are very similar from one person to another, though not precisely equivalent. The field of magical items has for the most part been the field of manipulating those channels; early items were usually weapons and armor, which touch only on the most surface-level aspects, and our ability to create more sophisticated items advanced slowly in early times, because we did not possess a good understanding of the principles at work. In a quirk of history, the first channels we learned to manipulate effectively were the ones we know regard as the most idiosyncratic and sophisticated: rings. Rings interact not with the local pooling of energy, but with a deeper level of soul-stuff. This requires fine control and is only possible for the most powerful of spellcasters, but it does not involve systematic understanding of the local flows of energy, and so was separable from the rest of the field. The various bodily affinities were gradually understood in bits and pieces, with the first attempts working only for a single type of effect, such as bracers of armor, and usually only in their weakest form - even early rings are, while powerful, much less powerful than we now know is possible. Also early were potions and oils, which operate using the internal magic channels but in a sufficiently consistent way that a rough, very descriptive understanding, without much grounding in theory, allowed them to create a variety of effects operating along similar lines.
It was in the heart of the dwarven empire in the reformed days where magic was no longer verboten that the first systematic understanding of the individual's magic channels began to be achieved. The first treatises written concerned specifically the channels in the legs and feet, but even this was enough to galvanize the field of item creation: methods which had previously been developed for boots of speed and greaves of stealth were, with the benefit of this systematic understanding of a piece of the whole, expanded to accomodate greater power within three decades, and to expand to a much greater variety of effects within two centuries. From there, the systematization tackled the arms and hands, which went much slower than previously because of misunderstandings caused by rings, which were at that time believed to operate only if found in the traditional shape and location of a physical ring. The insight that they were not interacting with the local channels in the hands allowed scholars to more directly analogize the hands to the feet, with rapidly-productive results when the barrier of misunderstanding was overcome. The community of crafters which discovered these principles was initially a guild system which guarded their secrets closely, but the overall concept of interacting with local channels was not kept secret as effectively. For this reason, crafters in other regions discovered similar principles but applied to other parts of the body. The elvish carvers first found the channels in eyes and were particularly effective in creating sensory-enhancement techniques, and then later generalized to the head and face. The core torso proved more difficult to map, though it has not particularly proven difficult to use once it was mapped; scattered druidic traditions managed to map the waist, but the full torso wasn't understood except in the later-developing study where both dwarves and elves, as well as other communities catching up to them, achieved full understanding of the whole body's map. This eventually unified with the methods used by potion-brewers and other makers of consumable-effect items such as the feather token into an overall set of methods. These take a very skilled craftsman to master the full range of applications, but the theory is consistent and understood by most wizards.
To complete the set of common crafting specialties, let me quickly digress on the spell-like items. Scrolls are as old as wizardry and have been rediscovered repeatedly; they are a minor variant of the notation and stabilized spell that a wizard places in their spellbook. The wand was known relatively early in history, definitely present in Lantide and brought to our continent by expatriates, but their creation was not actively passed down by the elves, and the principles needed were lost during the magic purges of the early dwarven empires. It was only alongside the systemization of magic channels that their creation was rediscovered, and understood as the self-contained 'prepared snare' of magical energy that we now use to create them, which is a mixture of the basic scroll with some techniques used for weaponry, creating a final product which can be used by an apprentice caster, a non-mage crafter, or by anyone who chooses to train in their use, which is common among adventuring fixers. The new - and, we believe, better-developed - theories also laid the groundwork for the staff, which combines the aspects used for weapons, the variants on those structures used for wands, and some fine-grained patterning most similar to rings, and created a powerful, sophisticated extension of a wizard's magical networks which allows a skilled spellcaster a much greater range of spells and can be, in a very real sense, a prosthetic extension of the humanoid body - which is why, unlike almost all other magical adornments and tools, it can be recharged from their reserves. It will come as no surprise to my audience that I am a carver of staves, and while I know several other varieties from earlier in my career I truly believe staves are the pinnacle of the crafter-mage's art. Or, at least, they are for now - perhaps in coming centuries we will advance our crafts and make new and yet-more-marvelous types, as our precessors invented staves.
The overall theory of items and the 'bodily affinities' which shape who makes things and why rests on the basic principle that a magic item functions by manipulating the magical channels of the one who uses it. There is a continuum, of course; weapons touch only very lightly, armor slightly more, and sophisticated items can be made to minimize the entanglement, the 'unaffilious' items. But the greater variety of wearable items all use close bonds to a particular part of the network, and have their effects by altering that network to draw on the spells and effects prepared in the item. Wearing two items which try to bond to the same part of the network will, at best, make one work at slightly-reduced capacity and the other not at all; the modified network created by one effect is the wrong 'shape' for the other to bond to it - unless, of course, one of the two has been crafted to not require it, but that is much more involved and takes, for a crafter practiced with both types, twice the time and materials. In principle there should be dozens or even hundreds of possible network sections which an item could bond to, but for the most part the modern crafter divides them into a standard set of twelve. While a few of these have clear delineations, such as the eyes, it is important for the student to note that most of these are essentially arbitrary. It is a fact that the channels in the vicinity of the waist are well-suited for effects which enhance the physical characteristics: strength, endurance, speed, agility. But while any system of crafters which developed independently but with the same knowledge base would make something very much like belts of giant strength, they would not necessarily call them "belts"; they might instead make breeches of giant strength and consider the lower torso part of a different affinity. The virtue of our standard set of twelve, however, is that it is widespread and covers almost all crafters who trade with us. If you create an item with one of our standard twelve affinities, you can be assured that it will interfere solely with other items made to use that same affinity. If you instead make breeches and make use of the channel segments lower on the body, you may have created an item which interferes both with the waist and with the knees and lower legs.
There is, however, reason to think this problem is not eternal. As our theoretical understanding grows more precise, it seems likely that we will find that some of these affinities can be subdivided, allowing more than twelve to be worn simultaneously. We know for certain the affinities are not perfectly interfering, from the art of 'kytoncrafting'. Like many other niche crafting methods, its origin is distasteful, coming from torture cults which revere the extraplanar kytons. But the methods are, when used with informed consent and restraint, ethical and fascinating. Kytoncrafted adornments embed into the flesh, interfering with the circulatory system of blood, and life-force directly, rather than primarily with the magical channels. The result creates wounds which never heal properly until removed, even with the aid of divine healing, but they do not interfere with traditional items utilizing the same 'body affinity', so that, for example, one may wear boots of speed together with ankle piercings of the spider, and have both function perfectly. To date, all attempts to refine this to remove the lasting injury have made them more difficult to create and embed, ultimately approaching the same end state as an unaffilious item. But it gives reason for optimism nonetheless; one boundary can be breached, and with time we can breach more.
