Marginal Harmonics

Default Attribute: Speed

Lore

Halfling magic is a secret so well-kept that most people don't know it exists.

The Halfling understanding of the Axioms arose not from scholarship or spirituality but from survival. Surrounded by lineages that were larger, longer-lived, and more conventionally powerful, Halflings evolved a relationship with the narrow probability layer of the Axioms, the harmonic band governing which of all possible outcomes actually manifests. They call this the Margin: the paper-thin space between what happens and what almost happened.

Marginal Harmonics is not mind control, precognition, or telekinesis. It is the ability to make the Margin favor you. A Marginal practitioner doesn't make the bullet miss; they make the chain of events leading to the shot slightly less likely to resolve into a hit. The camera doesn't glitch because of a spell; the precise combination of vibration, temperature, and processing load that would cause a glitch becomes marginally more probable at exactly the right moment.

The result is magic that is almost entirely undetectable. It looks like luck. Good Halfling operatives are not identified as practitioners; they are identified as unnaturally fortunate people, which is a very different threat profile.

Marginal Harmonics is Speed-governed by default, reflecting its reactive, reflexive nature. A Halfling investing in Speed for mobility and Stealth is simultaneously investing in their magical domain.

Mechanics Summary

Feature	Detail
Default Attribute	Speed
Action Type	Reaction or Minor (most effects); Free Action (passive Nudge)
Signature Feel	Invisible, passive-looking, probability-based; practitioners should never appear to be casting
Power Access	HIA Marginal Operative, Signal Scryer (Professions); HIA-sponsored Term of Observation
Signature Focus	The Loaded Die

Passive Appearance: Marginal Harmonics is specifically designed to be undetectable. Unless a practitioner is actively trying to produce a dramatic visible effect (which the Tradition is not suited for), no standard Notice or Investigation check will identify a Marginal roll as magical activity. Detecting Marginal Harmonics requires a specific Attunement check vs the practitioner's Tradition rating.

Disciplines

Nudge

The smallest push in the right direction.

Nudge is the foundational Discipline of Marginal Harmonics, the practitioner tips the probability scale on a single moment. It is subtle, fast, and cheap. It is also the Discipline most frequently misunderstood as simply "luck."

A Nudge does not guarantee an outcome. It makes a specific outcome marginally more or less likely, which in a world governed by dice pools and thresholds can be the difference between a critical success and a catastrophic failure.

Challenge Applications:

Force a re-roll of any single die in any roll (own or other's) once per scene as a Reaction, the new result stands (Threshold 1; this is the core application of The Loaded Die focus)
Create a minor environmental coincidence: a distraction occurs, a door was left unlocked, the guard looks the other way for five seconds (Threshold 2; Free Action if subtle; the "coincidence" must be plausible in context)
Impose Disadvantage on a single roll by an observed target within Near range as a Reaction (Threshold 2; the target perceives no magical cause)
Grant Advantage on a single roll for yourself or an ally within Near range as a Minor Action (Threshold 2; appears as "good form" or "a lucky read of the situation")
Create a cascading coincidence: a series of small events that redirect a target's attention, route, or decision toward or away from a specific outcome (Threshold 3–4; takes a scene to establish; appears entirely mundane)

Scaling: Excess successes on an Advantage or Disadvantage grant allow the effect to persist for multiple rolls (one per excess success) rather than a single roll.

Backlash: The probability inversion hits the practitioner, Minor: the next roll the practitioner makes is at Disadvantage regardless of circumstances; Moderate: the coincidence that was supposed to help instead harms, the door that should have been unlocked locks itself, the distraction draws attention to the party rather than away; Severe: a Probability Cascade triggers, for the rest of the scene, the practitioner's Wild Die implodes on 1–2 rather than 1 only, representing severely destabilized local probability.

Signal-Read

Perceiving the probability shape of a situation.

Signal-Read is Marginal Harmonics turned inward, the practitioner reads the probability layer of the present moment to perceive which outcomes are most and least likely to manifest. This is not prophecy. The practitioner doesn't see the future; they see the shape of the present, which tells them where events are trending.

The HIA's Probability Engines are large-scale Signal-Read systems, automating what a skilled practitioner can do intuitively. An operative using Signal-Read in the field is doing what a Probability Engine does for national intelligence, on a personal scale, in real time.

Challenge Applications:

Assess the immediate probability of a specific outcome: "Will this negotiation turn hostile?" "Is someone in this room lying?" (Threshold 1; GM provides a probability reading: very likely, likely, uncertain, unlikely, very unlikely, not a certainty)
Read the probability signature of an individual: identify their most likely next action, their strongest current motivation, and whether they are under Marginal Harmonic influence themselves (Threshold 2)
Identify a "Probability Seam", a moment in the near future when a small action will have disproportionate consequences, positive or negative (Threshold 3; GM describes the seam and roughly when it opens)
Retroactive probability read: assess what probability factors led to a specific past event, effectively a forensic tool for understanding how something happened and who nudged it (Threshold 3)
Password and access prediction: the HIA's legendary ability to guess passwords, combinations, or security responses on the first attempt, Signal-Read identifies the most harmonically resonant choice in a constrained set (Threshold 2 for simple systems; Threshold 4 for complex or randomized systems)

Scaling: Excess successes on a probability reading increase its precision, uncertain results sharpen to likely or unlikely, time windows on Probability Seams narrow.

Backlash: Signal-Read overwhelms, Minor: the practitioner cannot turn off the probability read; every interaction this scene is flooded with probability information, imposing Disadvantage on social rolls due to distraction; Moderate: a false Probability Seam appears with high clarity, the practitioner becomes convinced a specific action is critical and will pursue it compulsively until they pass a Wit Save vs Threshold 3; Severe: the practitioner's Marginal field destabilizes completely, broadcasting their harmonic signature, any Attunement check to detect Marginal Harmonics in the area automatically succeeds for the rest of the scene.

Obscurement

The art of not being where attention lands.

Obscurement is what separates the HIA from other intelligence agencies. It is not invisibility, the practitioner is physically present and visible to anyone who actively searches. Obscurement makes the practitioner statistically irrelevant to ambient attention. Security cameras don't malfunction; they just consistently fail to capture the practitioner's face with enough clarity to be useful. People in a crowd don't fail to see the practitioner; they simply don't find them interesting enough to register.

Challenge Applications:

Enter a passive Obscurement state: the practitioner becomes effectively unnoticeable to entities that are not actively looking for them, automatic success on Stealth in any environment where they are not the focus of active surveillance (Threshold 2; scene duration; Free Action to maintain once established)
Extend Obscurement to one ally within Close range (Threshold 2; both must remain in Close proximity)
Slip past active electronic surveillance without triggering alerts, not by hacking the system, but by making the practitioner's passage statistically improbable to register (Threshold 3; works against automated systems; does not work against live human observation without an additional Stealth roll)
Remove a recent memory from casual attention: a witness who saw the practitioner 30 seconds ago finds their recollection statistically fragmentary; they remember "someone" but not details (Threshold 3; does not affect focused, deliberate witnesses)
Establish an Obscurement Anchor in a location: the location becomes statistically difficult for non-invited entities to locate or remember, the address is hard to recall, GPS routes avoid it, and people who walk past it rarely think to look at it (Threshold 4–5; duration until deliberately dissolved)

Scaling: Excess successes extend the range of passive Obscurement or increase the number of allies it can cover.

Backlash: Obscurement inverts to conspicuity, Minor: the practitioner becomes the most visually prominent thing in the area for the scene, everyone notices them immediately; Moderate: all current surveillance on the practitioner (camera footage, GPS logs, digital records) from the last 24 hours is compiled and automatically flagged by relevant security systems; Severe: the practitioner's HIA identity record (real name, biometrics, cover assignments) is briefly broadcast on the local network, any Gnomish Network Presence practitioner or active surveillance system in the area may access it with a Threshold 2 roll.

Marginal Prediction

The full deployment of probability mastery.

Marginal Prediction is the advanced integration of all Marginal Disciplines, the ability to maintain a continuous probability read on an evolving situation and make real-time Nudge interventions based on it. This is the operating mode of senior HIA field operatives and the theoretical foundation of the Shadow-Census Probability Engines.

Marginal Prediction is not a single action but a sustained state. While active, the practitioner is simultaneously performing passive Signal-Reads and standing by for Nudge interventions, processing the probability flow of an entire scene as a continuous background operation.

Challenge Applications:

Enter a Marginal Prediction state: for the scene, the practitioner may perform one Nudge (re-roll) and one Signal-Read assessment per Turn as Free Actions without spending Primary or Minor Actions, at the cost of becoming Stressed immediately (Threshold 3 to enter; this state costs more Friction than a standard roll because of the sustained output)
Execute a Probability Cascade: a chain of six or more Nudge-equivalent interventions woven together to redirect a complex event outcome, a negotiation, a chase, a social situation, toward a specific result (Threshold 4–5; takes a scene to resolve; appears entirely like coincidence from the outside)
Counter a hostile Marginal Harmonic: detect and neutralize Nudge or Obscurement effects being applied to the practitioner or allies (Threshold equals the opposing practitioner's Tradition rating; this is one of the few Marginal applications that can be detected as magical by a trained observer)
Establish a deep-cover Prediction on a target: maintain a probability read on a specific individual even across distance, via Signal-Read, knowing their most likely current action, location, and state from afar (Threshold 4; duration: days equal to successes; requires initial close-range calibration)

Scaling: Excess successes on entering Marginal Prediction extend the state's duration or add additional free Nudge uses per Turn.

Backlash: The probability system overloads catastrophically, Minor: Marginal Prediction ends immediately and the practitioner cannot enter it again this scene; Moderate: the Prediction inverts, for 1D6 Turns, the practitioner's Nudge always produces the worst outcome instead of the best (GM applies this silently); Severe: a full probability storm, every character within Near range must roll their next action at Disadvantage as local probability destabilizes completely, and the practitioner takes 1D6 Psychic damage.

The Loaded Die (Marginal Focus)

Appears to be an ordinary die, standard weight, balanced, unremarkable. It is neither. The Loaded Die is inscribed with a Marginal Harmonic across every face, primed to enforce the highest-probability favorable outcome on any roll made in its proximity. It does not change dice. It nudges reality's interpretation of them.

Mechanical Effect: Grants +2D to Nudge and Obscurement rolls. Additionally, once per scene as a Free Action, the practitioner may use the Loaded Die to force a re-roll of any single die, their own or another's, with no roll required. The die simply comes up differently.

Availability: HIA issue only, to graduates of the Term of Observation. Each die is unique and harmonic-keyed to its owner, a Loaded Die used by a non-practitioner functions as a normal die. A non-Halfling practitioner who acquires one must spend a scene "attuning" it with a Marginal Harmonics roll vs Threshold 2 before the mechanical benefit applies.