Arcana

**Arcana** is a type of extraplanar matter that, upon hitting the Weave generally (except in certain rare circumstances) "burns up" into a form of energy (akin to other physical forms of energy, such as heat or magnetic energy). The term *arcana* refers both to the energy and to the material forms. Though not fully understood, arcana is the source of all magic in Ygdren, affecting creatures and objects alike and being the basis for any and all casting of spells of any form.

Like any other form of energy or matter, arcana is a conserved quantity. As per the law of conservation of energy, arcane energy can be converted in form but not created or destroyed. Similarly, as per the law of conservation of mass, the quantity of arcane matter must remain constant over time within a closed system. However, arcane energy can technically be reduced/increased if converted to/from arcane matter, the only exception to these laws of conservation. The two forms of arcana convert to and from one another in equivalence. An amount of arcane matter will always yield the same amount of arcane energy, and vice versa.

## Origin

Like other forms of matter or energy, arcana is a key building block of the universe at large, and has existed in some form since the beginning of time. It is converted to and from other forms of matter or energy via natural or artificial processes.

In the Prime Material Plane, it is theorised to be produced by the extreme forces at play in the cores of stars. Here, base energy is converted into heat, light, and arcane energy. Some of that arcane energy remains within the material plane, while the rest is expelled with such force that it passes through the planar barriers and into the Weave, where it bolsters the reserves of arcane energy there. This theory is backed up by the twice-yearly confluence events. In the Spring Confluence, when the two suns are most aligned, magic is at a peak. Vice versa, in the Autumn Confluence, when the suns are eclipsed by the moon, magic is at its lowest. Arcane energy that remains on the material plane will also over time dissipate back into the Weave.

In extraplanar terms, arcana is found in various states of both matter and energy. In the Outer Chaos it generally takes the form of scattered, agitated gaseous particles that slam into each other and cause wild magical surges in the emptiness. Further in, these particles condense into the river of liquid arcana of the World Stream, which rotates at immense speeds around the inner planes. Amounts of this matter will occasionally be shot out of the stream into the Slip and (with enough momentum) in towards the Elemental Chaos where they collide with the turbulent energy dispersing from the Weave to cause intense elemental surges of magic. Under extremely rare conditions, arcana can take solid form, which is where it is at its most stable.

## Energy Form

As a form of potential energy, arcane energy can be transferred into other energy types to cause particular effects on matter. When converting into base energy types (those naturally present in a material plane), a large amount of waste arcane energy is usually created as a by-product that, unless carefully controlled, can cause adverse effects. The most common use case for this type of energy transfer is the casting of spells.

### Natural Manifestations

Arcane energy in the material plane often mingles and gets trapped with base matter. Almost all creatures and objects have some amount of energy trapped within them, arcane energy included. Certain materials are more conductive of arcane energy (such as many metals), while others are capable of storing greater amounts of arcane energy within them (such as gems) before shattering. In living creatures, there is always some amount of arcane reserve that can get used up and builds up again over time, absorbed from the air, food, water, and so on. In more religious nations, this arcana of living creatures is sometimes synonymous with the creature's mortal soul. Particularly devout religions shun the practice of the arcane, since it diminishes this arcana (and therefore the soul), even if temporarily.

The effect of arcana on life and nature is a broad topic. The diversity of sentient life on Ygdren is thought to have developed by and large as a result of the heightened presence of arcane energy on the planet, more than likely a consequence of having a binary solar system. Flooding living organisms with arcane energy is observed to cause changes in biology akin to mutation, though these changes seem to have little rhyme or reason to them (at least as far as is currently understood). Many creatures native to Ygdren show signs of arcane impact on the evolutionary process, and some have even evolved to feed directly on arcane energy in place of base energies. One notable natural phenomenon that is caused as a result of arcane fluxes is the aurora. In periods of heightened arcane activity, auroras are often observed in the sky above, caused by chaotic arcane energy affecting matter around it.

The density of arcane energy across the material plane is not uniform, and changes over time in ebbs and flows, akin to ocean currents. By extension, the Weave also has regions of varying density. On average, arcana is more densely packed around landmasses, and less so on the ocean. Why this is the case is unclear, though theories suggest it is to do with the fact that land tends to receive more arcane energy via sunlight and release that energy back into the air where it eventually dissipates into the Weave. By contrast, arcane energy is diffused into bodies of water and becomes trapped there, causing a lessened presence of arcana in areas where land is distant.

This inconsistency in arcane energy causes issues when carrying out arcane operations over long distances, specifically when crossing oceans. Teleportation for example is more fickle, since it runs the risk of fizzling out halfway if it were to hit pockets of greatly diminished arcana. This creates a number of logistical problems with teleportation between the western and eastern landmasses. To date, a solution to the problem has not yet been found.

### Usage in Spells

The casting of spells in itself is a complicated process, which not many are capable of grasping. There are various ways that the process can be triggered, however in all cases the basic principle is the same: an amount of internal arcane energy is expended by the creature casting the spell to connect to the Weave and draw in more arcane energy that will fuel the spell itself. In essence, a spell is similar to a chemical reaction, where the internal arcana of the creature is the catalyst that propels it into fruition, but the actual supply of energy comes from outside the catalyst itself.

Much like other forms of energy, arcana follow strict sets of rules and obeys cause and effect. As a result, it is possible to manipulate the raw energy pulled from the Weave in a complex yet deterministic series of ways. In other words, pushing arcana in one direction will always have the same result, provided all variables involved are the same. In the context of casting spells, this is what the spell formula is responsible for. A spell formula can take many forms, but is usually a sequence of small energy manipulations that, when encoded all together, cause the desired effect. Figuring out new formulae is a complicated matter, often involving careful theoretical research and experimentation. Even small modifications to a formula can dramatically change the behaviour of the spell, often with dramatic results.

The ways of triggering a spell vary. Most commonly, the casting is innate. A creature will have a higher than average reserve of arcane energy within it that manifests instinctually, subconsciously creating the magical formula and causing the internal spark that pulls in arcana from the Weave and causes the desired effects. Sorcerers and Druids for example cast magic in this way, the latter drawing on energy from surrounding nature to serve as the catalyst, as well as their own. Warlocks also are similar, though in this case surplus of arcane energy is provided by an external figure, usually a non-divine creature of great power.

In other cases, casting is done via studious application of scientifically derived formulae. Many of these were first developed via observation of innate castings, to eventually define the theory of magic that evolved over time into many different schools. In this case, the spells are cast in mathematical fashion with specific knowledge and intent of the formula. Wizards and Artificers for example cast magic in this way. Similarly, Bards cast magic through specific musical patterns, which fulfil the same role musically as mathematics does for Wizards' formulae.

The third form of casting is via belief or conviction. This differs from the previous two forms in that the energetic connection is reversed. The Weave reaches down and forms a link with the internal arcana, rather than vice versa. In such cases, the magical formula is provided either by a patron deity in whom the caster has absolute faith or by such conviction in particular tenets that the raw arcana balances itself to conform to this belief. Clerics and Paladins of different gods employ the former method, while some Paladins that hold only strong conviction in their oaths follow the latter. It is worth mentioning here that oaths have a very distinct effect on arcana, playing on the threads of fate that bind all planes together and pulling arcane energy in around them. This fact allows such folk that do not directly draw power from a deity to still cast spells innately, without intentionally reaching out with their own energies to spark the spell.

The final, and least understood, form of arcane practice is that of psionics. Similar to innate spellcasting, the caster will reach out with their own internal energy to pull in magic from the Weave. However, instead of doing so by subconscious knowledge of magical formula, a Psion will simply force the connection through sheer power of will, breaking through the arcana and reshaping the energy in the desired way. Very few individuals are capable of attempting such a thing, let along succeeding.

## Material Form

As a type of matter, arcane matter follows many of the same properties of other types of matter. It can switch between states of matter and each state behaves similarly to what would be expected from a normal type of matter, with some key exceptions. Of particular note, in material form arcana exhibits an attraction to other particles of arcana, akin to the magnetic pull between certain metals. Over time, with no exterior influence, fluid particles of arcana will tend to congregate into denser clusters. This is directly opposite the standard diffusion behaviour of most materials, which tends to move from a region of high concentration to a region of low concentration. This behaviour is also exhibited between different states of matter. For example, solid arcana will tend to gather liquid or gaseous arcana around it.

However, despite tendencies towards denser states, actually converting into more fixed states of matter requires immense amounts of arcane energy to bind the particles of matter closer together, as well as very specific conditions to trigger the process. In its most common state, arcana is found as a dispersed gas in the Outer Chaos, gathering into clusters when speed and momentum do not force the particles apart. Whenever particles in this state collide, they lose some of their mass to shed arcane energy that causes sparks and surges of magic in the vicinity.

In the World Stream, arcana is instead found in liquid form, pulling in nearby gaseous particles and arcane energy into the maelstrom. It is unclear how this river of liquid arcane matter originally formed, however it likely was a part of explosive processes at the beginning of creation that became a self-sustaining system where immense rotational forces convert arcana between states.

The rarest form of arcane matter is in a solid state. Solid arcana can only be created under extreme conditions, and only naturally occurs in the Slip inside turbulent areas of extreme pressure. Here, arcane liquid that escapes from the World Stream is jumbled together with arcane energy and other forms of matter into hyper-condensed chunks of solid arcana of varying impurity. In some cases, these will continue to draw base matter to them, functioning as a core that pulls in energy around it, often leading to the formation of demons. The purer the arcana that forms the core, the more powerful (and typically the larger) the demon.

Should a chunk of arcane matter ever escape the confines of the Slip, it will often have gathered enough momentum to break through the surrounding planar barriers, either disappearing into the Outer Chaos and dispersing back into gaseous form over time, or very rarely sometimes crashing into the inner planes. Very few such artefacts exist on the material plane, and they are generally highly sought after due to their ability to draw in and channel great amounts of arcane energy. In theory, pure solid arcana would be able to fluidly channel infinite amounts of arcane energy without it directly affecting nearby matter (such as the wielder). In practice, due to the natural impurity of such artefacts, they will tend to eventually shatter over periods of extended use, and caution is generally advised with their handling.

## Limitations

As aforementioned, arcana follows most of the laws of other types of matter or energy. In summary, it cannot create or destroy matter or energy, except through equivalent exchange from arcane matter to arcane energy and vice versa. This means that a spell cannot create new matter, only manipulate it at an atomic form, causing expulsion of base and arcane energy as a by-product. Similarly, a spell can only transfer arcane energy into a lesser or equivalent amount of base energy, usually with an expenditure of waste energy involved in the conversion process.

From a spellcasting perspective, the casting of spells is limited by the amount of internal arcana that the spellcaster possesses. This arcana is required as a catalyst to any spell or magical formula, and if it is spent then the spell will simply fail to start or fizzle out. Similarly, the amount of internal energy required is proportional with the amount of energy being drawn from the Weave, which in turn scales with the amount of base energy that needs to be produced or the amount of matter that needs to be manipulated.