Vis is an energy field, or force, that permeates the world, and is the source of all life energy and magic on Terrilia. It is pervasive, appearing naturally in every corner of the globe. Vis does not appear to be at all like other fundamental forces, nor does it appear to be a physical material. Instead, it constantly 'bleeds' into Terrilia by unknown means, forming currents of itself and settling freely in and around the Materia of the world. For unknown reasons, possibly related to the source of Vis and its flow around Terrilia, some regions have higher Vis densities than others, leading to greater magical occurences in these areas. Likewise, some areas are Vis blackspots. In the worst areas, very little life is able to flourish, as living beings' Anima cannot absorb enough Vis to sustain life.    

Forms of Vis

  While all Vis appears to be effectively identical, it does manifest in several different ways, each of which has slightly differing properties and which, crucially, affect how the Vis can be effectively wielded as a tool.  

Free Vis

  Free Vis is Vis that has not been bound to an Anima or Materia, such as that found in Vis flows. It is the most abundant form of Vis, and is the ultimate source of Vis that is later bound. This is the form Vis takes when it first bleeds into Terrilia, and is the form bound Vis takes when it becomes unbound. Free Vis is usually inert until acted upon by an external force such as an Anima or rune, but in high enough densities its own eddies and currents can cause unpredictable magical effects such as shifts in gravity or bursts of light.  

Anima Bound Vis

  All living beings' Anima require Vis to survive. It has been known since prehistory that Anima slowly draw in free Vis from their surroundings, binding it to themselves and the body they sustain, using it to maintain life and to perform any magical abilities the being has. Upon death, the Vis bound directly to an Anima is released back into free Vis, but the Vis bound to the Materia of its body remains bound. Every Anima imprints a unique signature on its bound Vis, which can be detected by sufficiently skilled mages. The qualities of an Anima also determine how fast Vis is bound and used, and how it is utilised. This is explained more in the Anima encyclopedia entry.  

Materia Bound Vis

  Vis may also be found bound into the very Materia of which Terrilia is made. This can occur naturally, as free Vis can be slowly absorbed into various materials, or artificially, as a mage can direct their own bound Vis into an object of their choosing. Every material has different Vis binding properties, pertaining to the quantity of Vis that can be stored, how fast it may be stored or retrieved, and how stable the binding is. Over time, even the most stable Materia bound Vis will leach back into its surroundings. These properties are decribed in far greater detail in the Materia encyclopedia entry, along with descriptions of the various base forms of Materia.  

Vis and Magic

  Aside from its crucial role in maintaining life, Vis is the source of all magic on Terrilia. That is to say, magic is the manipulation of Vis in specific ways, directing and using its flow. Most commonly, this manipulation is performed by the Anima of a living being. To give an example, a mage may lift a rock by sending out a stream of their bound Vis, and funneling it into the correct pattern benath the rock. The Vis pattern will exert a force upwards and the rock will be lifted.   Vis flows also have their own 'momentum', and by utilising this it is possible to cause magical effects that last a little longer than the initial influence. Using the above example, the mage may push the stream of Vis skywards below the rock, and the resulting flow will maintain the effect for several seconds without further input, continuing to accelerate the rock. Objects may also be enchanted for short periods using this method; by carefully building a pattern of Vis with the desired effect in a material, the magical effect will continue until the Vis is completely consumed or the pattern disintegrates. Examples of this use of Vis include temporary barriers in the air, or swords that are enchanted for extra toughness during battle.   While most Vis manipulation is the deliberate work of an Anima, there exist rare natural phenomena in which Vis patterns have formed in such a way that they create a natural magical effect. Some of these are transient, lasting only until the pattern disintegrates, but some appear to be self sustaining and have been occurring for centuries, such as the floating rocks of Althuria.   As with earlier sections of this entry, the subject of magic and Vis manipulation is discussed in greater depth in the Magic encyclopedia entry, and associated articles.