Mana
You know what mana is. It is an invisible, colorless, odorless, tasteless, soundless essence that exists in the world in the same way that many other elements such as oxygen, nitrogen, etc. exist in the world. Every creature in Sedaia has a sixth sense in addition to their other five senses: commonly called "mana sense." It is useful for gauging how much mana remains inside one’s own body, and sensing very mana dense areas in nature. Mana can be used by the body, again in the same way that natural elements can be broken down and used by it. Mana can be expended to cast magic, and it replenishes naturally over time, although one can become fatigued by using too much at once.
Every living thing has the ability to utilize mana, from the most regal of human beings to the lowliest weed in a swamp. Magic is a common part of people's everyday lives, although of course some are better at using it than others. Those who dedicate their lives to the study and development of magic can become powerful mages, but others such as simple farmers or laborers may only use their own magic for small things like lighting a lantern. Plants that excel at using mana have unique properties to them, and can be used as food or medicine in the same vein that non magical plants can, bestowing unique effects. Animals that excel at using mana can quickly become dangerous beasts, and entire species that have high magical aptitude are commonly referred to as "monsters."
Magic
While other creatures become monsters, when humans have high magic potential they become
mages. To date, there are
three disciplines of magic.
Elemental magic,
Arcane magic, and
Blood magic.
Elemental MagicThe most common of magic in Sedaia. Humans can find it difficult to work with something they can only vaguely sense, so in order to better use mana they use it only as a catalyst to manipulate the more familiar. Like it's name suggests, elemental magic involves the summoning and control of classical elements: fire, wind, water, and lightning. This is achieved by actively transforming mana into these elements. Most common folk in Sedaia are attuned to only one single element, but it is not impossible to learn and master more. Although most only use their magic to supplement their daily lives, dedicated mages can find work in various occupations. A mage may endeavor to discover new types of mana control at a college, work as a magic tutor to those less gifted in using mana, or may even be employed in more physically demanding jobs - for example, a wealthy ship's captain might hire a trio of wind, water, and lightning mages to keep his vessel as safe as possible while at sea.
Arcane MagicThis discipline of magic is the most difficult to learn, and there are extremely few masters of the arcane. Where elemental magic turns mana into elements, arcane magic alters the mana itself to grant properties to it without changing it from it's original state. It requires precision and in-depth knowledge and understanding of mana to pull off. When common mages visualize mana as fire, and thus transform it directly into fire, an arcane mage may be able to heat up the mana itself, making a hot spot. It can give mana a physical presence, either by making it visible or otherwise known to the other senses besides mana sense, without transforming it into another state of matter. Other uses include imbuing mana with energy, such as consecrating a specific area with "holy" attributes. The lost art of imbuing mana into objects, giving it attributes and shape and forcing into a vessel in order to be used later, is called enchantment - and it is considered the ultimate use of arcane magic. Scholars strive to recover this lost art. Mana stones, precious gems or minerals imbued with magic, are remnants of an age where enchantment was common, and the few left unspent in the world fetch exorbitant prices.
Blood MagicBlood magic is the easiest form of magic to learn – but also the most dangerous. Because of this devastating combo, blood magic in all its forms is forbidden by law in Sedaia. Like elemental magic, it involves using mana as a mere catalyst. Because mana courses through the blood of all living things, using blood as a physical vessel for mana makes casting magic using a blood catalyst relatively simple. Through this method blood can be transformed into elements, a once common and harmless practice, but blood magic can also be used for much more. Curses and hexes, dangerous spells now more or less lost to time, originated in this discipline. It can twist the flesh of living beings, altering their body to both positive and negative effects. Blood magic can leave permanent, lasting damage on individuals and sometimes entire bloodlines. This kind of magic can also be used in heinous rituals to raise the dead, resulting in shambling corpses. Although most that secretly practice blood magic will never even think to use it for dark purposes, the threat exists - and so it is unlikely it will ever be legal to practice again.
Monsters
Plants and animals that have the ability to use
magic become creatures known as
monsters. Monsters can be individuals, like a local dog that awakened to it's potential and transformed into a deadly
frost wielding hound. They can also be entire species, such as devastating
plant-like abominations that can be found deep in several forests throughout Sedaia. It's safe to say that many classic fantasy monsters can be found in the setting, for example: cockatrices, chimeras, manticores, dragons and wyverns, gryphons, basilisks, phoenixes, leviathans, and more.
Magical illness, though uncommon, also exists in Sedaia. From plagues that affect one's ability to manipulate mana to diseases that physically alter the body such as lycanthrophy, contracting any magical illness is grave news. No one quite knows how such sickness came to be, though the prevailing theory are curses so strong they take a life of their own.