With enough magic, you can make the world a perfect place, but in the same instant you will destroy it. -Orthophysi maxim
Magic is the catch-all term for the power to change the world through supernatural means. Given that it deals with forces beyond natural experience, magic is not a science and does not always follow the expectations of human reason. Depending on the source of the power it can be extremely effective and provides a tempting shortcut to achieve many of the desires of mortals, both good and ill. Because of its power and transcendent nature magic is also extremely dangerous, and without proper respect can cause untold destruction.
The guide below lays out the workings and basic lore behind magic in Polemos, which is intended to give a "grounded fantasy" flavor. It should be noted, however, that these rules are closer to guidelines and can certainly be adjusted to reflect the preferences of your gaming group. For a more traditional fantasy flavor, simply ignore the concept of "magic backlash", and optionally remove the concept and abilities of the orthophysi. Alternatively, you can disallow all [magic] tagged skills, abilities, talents, etc. for a straight "low fantasy" flavor.
When magic is manifested in Polemos it causes a "backlash." Breaking the complex and interconnected laws of the natural world causes a reaction, but it is not always equal or opposite. The only reliable exception to this is the use of divine magic - i.e. miracles done through the explicit permission of nature's Creator.
Magi have diverse methods to invoke their powers, often dependent on their magical school or tradition. The most common is through the speaking ancient and powerful words; while others may use special hand signs, cast lots, trace out magic circles, or some other ritualistic or mystical action. Characters may choose what form their individual invocations take, but for gameplay purposes invocation methods are always, unless specified by an ability, obvious to witnesses through both sight and sound. People may not understand what is occurring or may not even believe magic is possible, but they will understand the magus is trying to cast a spell.
Magic in the 4th age is a relatively common, if sometimes controversial, sight. In the Great War Eleshites practiced unrestrained magical research, and angelic forces approved the use of powerful magics to oppose them. In most regions there are at least a few permanent scars on the landscape showing the consequences of magical warfare. In some places the world is still broken, with widespread dangers borne from natural laws remaining twisted or unreliable. During the 4th age magical arts are diverse and not always formalized, thus it is common for magi to experiment and combine well-tested traditions. Conversely the need to control magic is relatively obvious and easy to argue for, and so orthophysi are commonly organized and well-funded.
While there are more advanced methods, the recommended way to play as a Magus (i.e. a magic user) in Polemos is for a player to:
Note that while most talents represent inborn traits of a character, a GM may consider letting a character gain magic power and magical training talents later on, either through a story event or through an XP purchase. The GM can determine the XP cost, but at least 12 XP per talent is recommended.
To use magic, a character needs:
Magic points (MP) represent an abstract amount of magic power, which can come from a variety of sources reflecting the diversity of magical knowledge and craft. Most magi specialize in a single magic source, but they are not inherently exclusive.
One common way to manage the effects of a magic backlash in the 4th age is to deflect it into the chaos of the celestial realms, where its effects will (hopefully) dissipate harmlessly. This does not eliminate the need for justice in breaking nature's laws, however, and so the backlash will return in more subtle or pernicious ways. This justice is not always immediate and doesn't necessarily target the Magus specifically. The world collectively suffers the consequences, but the effects are most often localized either to the Magus or the site of the magic use. This justice is represented through the use of divine justice effects.
Other than during the Great War of the 3rd Age, the number of spirits interacting with the mortal realm is at its highest during the 4th Age, to the point that it would later be called the 'Age of Visitation.' These interactions take a myriad of forms, from ghosts haunting old battlefields to forest wisps confusing travelers to demonic possessions to angelic proclamations.
One form of interaction popular with magi that has become the basis of many magic traditions is the "spirit pact." While sometimes going by another term, it takes the form of a voluntary mutual benefit agreement between the magus and the spirit. The spirit pledges access to their magical power and permission to potentially summon the spirit to protect the magus. The magus pledges to serve the interests of the spirit in the natural world, acting as a sort of proxy for the causes and goals of the spirit. The process of forming the pact differs between traditions, but one constant is the requirement that both parties must know each other's true names.
Spirit pacts are usually non-exclusive, meaning the magus can have multiple pacts with spirits, and a spirit can have multiple pacts with magi. There is no strict limit to how many pacts a magus or spirit can be part of, but since they make more attractive pact partners it usually follows that the more pacts someone has the more powerful they are. Spirit pacts can be broken at any time by either party, but contact between worlds is not quick and replacing a pact partner is not easy, so breaking a pact is not often taken lightly. Also, given that both parties have shared their true names, they can still easily affect each other with forms of remote magic even after the pact ends, so hostility between pact partners is rare even if the pact is broken.
Characters that make use of spiritual magic should keep track of a list of spirit pacts they have, as well as a loyalty modifier. This loyalty modifier is not used as frequently as during riding, but should generally follow the same range and guidelines. When a magus performs actions or gives offerings pleasing to the spirit they should gain loyalty (generally a single point), and similarly lose loyalty when they do something the spirit dislikes. Spirits can generally observe a magus from the celestial realms so loyalty can be gained or lost even if the spirit is not currently summoned to the natural world.
When a spirit is disloyal, typically represented by a negative loyalty modifier, it is unlikely that they will heed any call for magic power or summoning. Even loyal spirits will not contribute to actions they are gravely opposed to. For example, an angel wouldn't obey an order to murder an innocent while summoned even if they are otherwise loyal.
As a result of the Great War of the 3rd Age, many magical objects can be found across the world that were either intentionally created during the war and left behind, or accidentally absorbed nearby magical power unleashed by the conflict. For this reason objects with magical power are often called "artifacts", even though new objects may be created by magi.
Artifacts have a maximum MP rating just like magi, along with zero or more magical effects called "enchantments." Enchantment effects typically reserve artifact MP instead of spending it, and allow the enchantment effect to occur when a certain condition is met. For example, an enchantment on a sword might reserve MP to allow a spell to be cast by its user, or deal some form of supernatural damage when the sword is used in a physical attack.
Enchantment effects are often added from magical abilities, though the GM may create or allow custom enchantment effects as desired. Like abilities used in a character's turn, an artifact can only have a single enchantment effect of a given name at one time, using the base ability or replacement name of a magical ability. If an effect of the same name is added to an artifact, it overwrites the existing enchantment effect.
When abilities are used for enchantment any decisions made during the ability, such as variable MP cost or "may" clauses, are made at the time of enchantment. Abilities with conditions on those decisions can be made during enchantment as if the condition occurs, but must include any extra costs as well, and the condition still applies when the enchantment is triggered. For example, if an ability allows for a decision of dealing extra damage at extra cost if the target is prone, the extra damage and cost can be included in the enchantment, but the extra damage will only apply if the target is prone when the enchantment triggers.
Elemental magic in the 4th Age seeks to manipulate aspects of nature that appear fundamental to its order and balanced by others. In the 4th Age there are seven elements, each balanced by two others:
In the 4th Age of Man it is common knowledge that the use of magic directly caused the collapse of the late 2nd Age, which in turn led to the horrors of the 3rd Age's Great War. Given that history it is not unreasonable that many see magic as a risk not worth the benefit.
An Orthophysis (plural: orthophysi) is a broad label for the individuals and groups that seek to limit the use of magic in the natural world. While there is no formal coordination among them all, they broadly agree that natural laws should not be broken and generally have no trouble working together, if only temporarily. Many Orthophysi come in the form of trained anti-magi - magic users that use their powers to dampen or nullify magical effects, others may be priests with no magical ability, or simple laborers that have strong revulsion to seeing a Magus at work. Orthophysi can certainly be zealous and cruel, but that is by no means universal. Many simply want restrictions on when and how magic is used according to other cultural norms. For example, many orthophysi in Agothos are happy with colleges training credentialed magi, but want to punish unlicensed use of magic and have strict rules about the use of magic during days when the Senate is in session.
Playing as an Orthophysis provides a good opportunity for players to "have their cake and eat it too" with regard to magic use. Characters can be interested and studied in magic, but limit the social and material backlash they produce.