Prime is one of the ten Arcana of Mage: The Awakening, and the Subtle ruling Arcana of The Aether. It may be best described as the magic of magic; it controls the basic energy or "particle" of magic, the prima materia that mages usually experience as Mana or Tass. Knowledge of Prime allows mages to manipulate this energy, allowing a mage to alter the spells of others, imbue mundane objects with magical properties, and manipulate resonance and auras. The Arcanum of Prime deals with magic in its raw and unrefined state, wielding the Supernal Fire directly on the Fallen World, rather than merely altering its facets. A mage skilled in Prime can create illusion, dispel the works of other mages, shield herself from magical power, tap the power of tass, read the nature of a being through its aura, and hurl bolts of divine fire, the most powerful offensive weapon in Awakened society, according to its primary weilders, the Obrimos. So far, nothing has been found to dispute their claims.
Hallows, illusions, magical imbuement, Mana, Patterns, resonance, spellcasting, and tass.
Nature and Power
The Arcanum of Prime is the Subtle Arcanum of the Supernal Realm of Aether, a realm that also produces the Arcanum of Forces, Aether seethes with magical energy. The realm is described as having rains of Mana, falling from the storm-wracked sky to the burning earth below. The very air is charged with mystic potential, the power of mighty works hanging over the landscape like a dense fog. Such is the power of Prime in the Aether that the whole realm is suffused with its glow, giving it an unearthly and terrible beauty. The Fallen World is nowhere near as magically charged as Aether and the Supernal Realms, but Prime still holds some power there. Of all the Subtle Arcana, Prime's influence has suffered the most by the gulf of the Abyss. Before The Fall, the universe was awash with in magic; now one cannot even cast the simplest spell without risking the invocation of Paradox. However, magic still exists, the Ars Mysteriorum is still humanity's best defense against the darkness, and the power of Prime is an effective tool in wielding and controlling these mercurial energies.
Magic is used by many, and a wielder of Prime can gain considerable power over all these people, simply by rendering their arts useless. A mage skilled enough in the Arcanum of Prime may work many wondrous and powerful changes upon the magical nature of one's surroundings, to the point where a true master can create Hallow and siphon the Essence from spirits or ghosts. One can pull Mana from Hallows or tear it from regular objects, making anything a potential source of power. The mage can dispel the efforts of any mage with ease or simply create a potent shield against magic energy rendering attacks and curses, null and void. One can see resonance and auras directly, detect and alter the ley lines of the world, bending these currents of magical energy to one’s whim. One’s powers can weave complex illusions, simulacra that can perfectly mimic anything one desires, or one can conjure up the destructive power of raw magic to rain destruction upon one’s enemies. A mage with the power of the Arcanum of Prime is a useful ally and a powerful foe indeed. Mage Sight using Prime, "Supernal Vision", is generally the most potent for examining resonance, though other Mage Sight spells are better for specific types of resonance. Supernal Vision also allows the caster to view a supernatural being's true nature. Another very useful application is in counterspelling; Apprentice knowledge of Prime allows a mage to counter any spell without knowledge of the Arcana used by the targeted spell. A mage who is an Apprentice of both Prime and Space gains the ability to supernaturally sense when others scrutinise or tamper with her active spells. This is known as "sensing the threads", and Prime magic may also be used to thwart this ability. 
Levels of Mastery
An Initiate of Prime, using the first level of mastery, can see resonance more proficiently than with any other spell. One can also detect and analyze enchantments in items, and see through illusions (depending on the respective skill level of illusionist and observer). One gains a limited ability to dispel magic, though one must have knowledge of the effects being dispelled. Lastly, one can record one’s rotes in a grimoire, that the mage or another might use them.
An Apprentice of Prime has the power to bestow one’s resonance detection upon others. One may counter spells from any Arcanum, or create armor against enemy spells (though not against regular damage like punches, or guns). The mage’s aura may be altered, making one appear as something one isn’t, and one may create the dueling circle for the Duel Arcane, a ritualized form of wizardly combat. One may also cloak oneself from the mystical senses of other mages as one alters or examines their magic, and may activate Artefacts and imbued items without needing to fulfill their triggers.
A Disciple of Prime may bestow one’s shield against magic, or alter the aura of, other creatures. One may channel Mana directly from Hallows or take it from inorganic tass or enchanted items, or dissolve said tass. The mage’s power over dispelling increases, allowing one to selectively dispel magic from some targets while still keeping the spell active against other targets, fortify the souls of targets, making them more resistant to attempts at soul theft, and one can imbue spells into items or make weapons and equipment capable of affecting Twilight or Shadow Realm creatures. One may transfer one’s Mana to other living creatures, create wellsprings of power from the ley lines that straddle the Earth, or weave simple, immobile illusions. Finally, one may wield the raw energy of magic as an offensive weapon, blasting at her foes with Supernal fire, not even arch masters can withstand Supernal energy for long, unless they kill the mage channeling this power they will eventually be burnt to ash.
An Adept of Prime can dispel any spell encountered without needing to understand the workings behind it. One may reactivate the flow of Mana from dormant Hallows or suppress active Hallows into temporary slumber. One may bestow one’s perception of magic and the arcane upon even Sleepers at this level of power, allowing them to glimpse into the magical world without fear of invoking Disbelief. Mana can now be siphoned from the Essence of spirits, loci, and ghosts or pulled from regular, non-enchanted objects. The mage can now also create animated illusions, but it still needs to be actively animated by the mage; they have no free will or mind. Finally, one may create functioning illusory objects, weapons or armor, which affect the world like regular such items would.
A Master of Prime to create complex illusions with a semblance of proper function, such as “working” computers or convincing shock troops. One can now siphon Mana from unwilling mages or create one’s own temporary Hallow to draw power from. One can also expel Mana from a given area, creating a ‘dead zone’ in which magic cannot function, though this may endanger the lives of creatures within the zone.
Archmaster and Above (●●●●●●+)
Archmasters are rare but not unheard of. They don’t follow the same rules as the other ranks. Archmasters become Avatars of the Arcanum they studied, living embodiments of the Watchtower their power comes from. They become conduits for power and are no longer barred from their power by the Abyss and so aren’t subject to Paradox. They take on the physical characteristics of their Arcanum. They should be addressed as Arcs (i.e. an Arc of Prime). Archmasters can cast all the spells from Initiate to Master, without using any Mana, and in any preferred duration. They gain the powers of a God, including limited immortality (e.g. aging is slowed down), but they’re still human beings and can be killed just like anybody else, but only if they get careless. They still suffer penalties of their Inferior Arcanum. A mage can’t over come that until he/she has become the Arc of that inferior Arcanum. Archmasters no longer belong soully to the planet of their birth they now become citizens of the cosmos, so their concerns must move beyond their planets to our Universe.
Archmasters of Prime sometimes emit a faint light. While it doesn't make them glow in the dark, it does make them easier to find if someone shines a flashlight on them. Arcs of Prime can create Hallows anywhere they want and even control the quality of the Mana and tass it produces. They're good friends with the angels who control prima materia in the Aether.