Physiology of the Arcane

Magical Manifestation

The study of the Arcane has long gripped the minds of Scholars and dreamers alike. Isekai's very air and soil are rich with magic and creatures that naturally use it, some as easily as breathing. Despite the lengthy history mortals have had to puzzle through the intricacies of magic, there is so much mystery left to unfurl. Many of these secrets are either not known by the Divine Races or they are not willing to share what they know. However, the basis of mortal knowledge is summarized best as the concept that magic is a natural energy of various colors, as explained in The Spectrum of Magic, while the interaction of sentient being with said energy is a matter of reactive biology.
All creatures, objects, and substances throughout the world of Isekai have naturally occurring energy that exists within the same space on an ethereal plane that is closely linked to the physical existence. Sentient beings possess a spiritual presence, a physical presence, and an ethereal arcane physiology that roots both of these things together to create what is known as a sentient existence.

Manifestation

Magic is an energy separate from but similar to that of spiritual energy. While spiritual embodies the willpower that sentient beings hold to affect change in the world, magic is an energy that permeates all substances and beings to varying degrees. We know these to be divided into distinct colors based upon function which often dictates the form that is inhabited by a given color of magic. Unless magic is used to invoke presence in the physical world it exists as an energy that is subservient to greater volumes of opposing energy, devoid of characteristic during interaction in the ethereal realm.

— The Spectrum of Magic

All creatures and all professions have a connection to magic that is based on their biology and is honed through their physical and mental experiences. While some creatures may not cultivate this skill, it is innate to them and neglect of it is similar to neglect of one's physique. The modern understanding of this physiology is that a sentient creature will always have a root, the ethereal connection that anchors a spiritual and physical existence together, and a system of stems that flow throughout their physical and ethereal forms to reactively attune to magical energy over the course of the creature's lifespan.
Sentient beings from the mortal realm exhibit the potential for Red Magic immediately as it is the natural byproduct of spiritual energy and magical energy existing in the same space. They are able to harness this magical energy through the use of innate biology known as stems. All living creatures exhibit varying types of stems that run throughout their body and enable them to sense, react to, and harness magical energy.
Stems are a complex field of study as they are the means by which the capacity and aptitude for various colors of magic are used. Stems are influenced by a variety of factors over the course of a creature's life to include:

• Species of Origin
• Repetition and Training
• Exposure to Magical Energy
• Educated use of Magical Energy
• Physical mass of the creature

Stems are an ethereal organ in sentient creatures, similar to the nervous system, that cannot be interacted with by using physical tools. Stems do not take up physical mass within the body but instead exist as an ethereal organ that runs throughout the body. Generally, this means that creatures with larger bodies may begin life with a higher capacity for using magical energy though certain species or methods of training can intensify the density of a creature’s stems. This organ can exhibit a few characteristics to include:

• Overall Mass
• Density overall or in a specific part of the body
• Color
• Shape

The root is the origin point of the stems in a living creature or an enchanted object, the direct point of connection between a living creature and the metaphysical structure that allows them to wield magical energy. While it is difficult to directly interact with this or even ascertain the exact position of it in some creatures, should it sustain injury, the creature will face great difficulties in harnessing magical energy or may even be cut off from it.
Stems are highly reactive, meaning that while a creature’s heritage and initial body size influence them at the beginning of said creature’s life, the stems that a creature possesses can change wildly over time. The density is affected by how much, how little, or in what way they are used to harness magical energy while the color corresponds to how well a creature can use that specific color of magic. Many Knights and high-caliber Swordsmen exhibit dense red-tinted stems that augment their muscle fibers and skeletal systems, allowing for incredible feats of strength and speed. As opposed to accomplished Wizards that typically exhibit white colored stems that are concentrated in the head and extremities with density corresponding to their level knowledge.
The shape of stems change based upon how a creature chooses to harness magical energy or in what manner they employ a specific color of magical energy. For instance, an elemental Mage will draw upon magical energy in the environment in order to assert command over it. They draw energy into their stems and internal system from the natural world and then harness it to enact specific effects as desired according to their capacity and skill. These stems often appear to have many thin branches around the edges with a number of offshoots that can help to maximize the ability to draw energy in from the outside. In contrast to a martial artist that will harness spiritual energy and create Red Magic from within to enhance their own body beyond regularly understood limitations. These stems will have an appearance of being thick and gnarled with rough edges and concentrated swirls near areas that are often empowered or used as points of contact much like the calluses on their body develop from striking.
These observations across the majority of sentient beings confirm that magic is an energy that is almost always intertwined with life save for a few rare cases in which a creature is completely devoid of stems, or an area that is designated as an anti-magic zone. An anti-magic zone inhibits a creature or magical item from harnessing magical energy by removing all magical energy from an area save for small amounts within their body. This explains a definitive feeling of sickness or weakness by powerful, magical beings or skilled spellcasters when they enter an area devoid of magical energy.

Colors of Magic