The Mana Purity Index
In the modern arcane age, no measurement has shaped magical society more profoundly than the Mana Purity Index — known universally as MPI.
It is not a title. It is not a rank. It is not a family honor.
It is the measurable truth of a soul’s capacity to wield mana.
The Mana Purity Index is a standardized 1–100 scale used to quantify the innate strength, stability, and efficiency of an individual’s Mana Core. Where lineage once determined status, MPI determines potential. Blood may influence it, but blood does not define it.
To understand MPI, one must first understand the Mana Core.
Every mana-born individual possesses a Mana Core — a metaphysical organ formed during early development. It anchors the individual to one of the Six Mana Lines and acts as both generator and regulator of magical energy. The core does not create mana from nothing; it draws upon the planetary current left behind by the Flamefall and filters it into a usable state. The strength of this filtration process varies dramatically between individuals.
MPI measures that variation.
It is a composite index derived from five core arcane properties observed in controlled testing environments.
Core Density measures the structural integrity of the Mana Core. A dense core withstands high-output casting without distortion. A fragile core fractures under strain, producing unstable spells or long-term damage.
Flow Conductivity measures how efficiently mana travels through the body’s meridian network. These meridians are invisible channels that distribute mana from the core into limbs, breath, and focus. Poor conductivity results in slow casting, physical backlash, and fatigue.
Resonance Stability measures harmonic coherence. Mana vibrates at a frequency unique to each individual. Stable resonance allows precise spell shaping even under stress. Instability results in surges, miscasts, or wild fluctuations.
Regenerative Throughput measures recovery. After mana is expended, the core must replenish its reserves. High-throughput casters recover rapidly, allowing sustained engagements or repeated spellwork.
Attunement Precision measures shaping accuracy. Raw mana must be structured into functional spell geometry. Precision determines efficiency, control, and resistance to interference.
Each property is evaluated during formal testing and combined into a single numerical index. The result is the Mana Purity Index.
MPI stabilizes during adolescence, typically between the ages of twelve and sixteen, when the Mana Core completes structural maturation. After this point, training improves technique and efficiency but does not meaningfully increase raw MPI. The ceiling is set.
Testing is conducted using a Resonance Prism Array — a calibrated crystal lattice developed during the later Conduit Age. The subject is observed under controlled emission, sustained channeling, geometric shaping trials, and stress exposure. The Array records harmonic distortions and output thresholds, converting them into a final index score.
MPI is not solely hereditary.
Magical bloodlines increase the probability of high MPI expression, but spontaneous variance is well documented. Children born to non-magical families have tested above 75. Conversely, noble houses have produced Null-Line offspring.
Environmental factors during early development appear to influence core formation. Proximity to wild mana wells, ambient saturation levels, maternal spell exposure, and rare resonance anomalies have all been correlated with elevated scores. The exact mechanism remains debated within Ossirian scholarship.
The 1–100 Scale
1–10: Mana Inert
Trace resonance only. Casting requires artificial amplification. High risk of backlash.
11–25: Low Channelers
Capable of minor structured spells with assistance. Conduit reliance common.
26–40: Functional Casters
Reliable low-tier spellwork. Often civic mages, artisans, healers.
41–60: Established Adepts
Strong reserves and sustainable casting. The backbone of magical society.
61–75: High Adepts
Exceptional control and stamina. Rare and heavily recruited.
76–90: Prodigy Class
Arcane anomalies. Rapid learners with significant output capacity. Often capable of conduitless casting at scale.
91–99: Archonic Tier
Extremely rare. Mana density approaches mythic thresholds. Capable of environmental-scale influence.
100: Theoretical Apex
No confirmed living subject has reached this index. The score remains a mathematical possibility.
Culturally, 75 marks the Prodigy Threshold. Above this point, casting shifts from exertion to instinct. Mana responds with minimal resistance. Such individuals are often identified early and courted aggressively by academies and bloodline houses alike.
MPI governs more than prestige.
It determines maximum mana reserve, safe overcast threshold, recovery speed, resistance to corruption, and compatibility with advanced conduits. High-grade relics often reject low-MPI wielders outright. Conversely, extremely high-MPI individuals may destabilize lesser conduits through excess output.
MPI can decrease through catastrophic core trauma. Severe overcasting, mana poisoning, or resonance fracture can permanently scar the core, lowering measurable capacity.
Increases are rare and unpredictable. Accounts of Mana Baptism, Soul Fusion, or near-death resonance events suggest marginal elevation in surviving subjects, but these cases remain exceptional and often fatal. Ossirian doctrine treats MPI as effectively fixed.
Statistically, fewer than one percent of the population measures above 75. The majority of Mortalkin fall below 30 and never develop casting ability beyond minor tricks. This uneven distribution underpins the political and educational structure of the magical world.
Yet MPI measures potential, not mastery.
A disciplined adept of 52 may defeat an untrained prodigy of 80. Strategy, knowledge, and composure remain decisive factors. The Index defines capacity — not character.
Among certain Archivist circles, a controversial theory persists: that extremely high MPI readings may indicate partial harmonic overlap with Ambient mana itself. If true, prodigies are not merely stronger — they are closer to the creative substrate beneath elemental classification.
This remains unproven.
What is proven is simpler: magic leaves a measurable imprint on those who can bear it. The Mana Purity Index is the world’s most precise attempt to read that imprint.
In Ossirian Deep, every initiate learns the same lesson upon receiving their number:
The Index reveals your ceiling.
What you build beneath it is your own.