Arc Theory
AX.GAT.08.06 - Arc Theory
The Ashori have never called it Arc Theory. They call it the Current, or working the Current, or in some communities nothing at all, a practice that predates formal naming, that was already old by the time anyone thought to document it. The term Arc Theory comes from the engineers and Survey Corps practitioners who encountered Ashori electrical capability and spent years reverse-engineering what they were seeing into a framework that non-Ashori could study and apply.
The name stuck because it is accurate. The tradition is, at its core, a theory, a set of principles about how bioelectric charge interacts with the electromagnetic character of station infrastructure, constructed materials, and living systems, and what a trained practitioner can do with that interaction. Engineers who develop it without Ashori biology are working from the outside in: learning to generate and direct charge through discipline and focus in ways their bodies do not do naturally. Ashori who develop it formally are working from the inside out: taking a biological inheritance and extending it into deliberate, structured capability that the biology alone cannot achieve.
The difference matters in practice. Ashori practitioners describe the tradition as a refinement, as the moment when the Current, which has always been there, becomes something that responds to intention rather than emotion. Non-Ashori practitioners describe it as the moment a set of theoretical principles becomes something they can feel. Both arrive at the same place from opposite directions. Most practitioners, regardless of origin, eventually stop thinking about the distinction.
What Arc Theory is not: it is not programmatic control of systems. A practitioner who powers a locked console does not thereby command what the console does; they deliver charge, and the system responds to charge the way it always responds to charge. The tradition interacts with the physical and electrical reality of systems. What those systems are programmed to do with that interaction is outside the tradition's scope. Practitioners who forget this distinction learn it again in the form of a very loud lesson.
System Integration
Arc Theory as an Odd Talent
Arc Theory functions as an Odd Talent per AX.C.04. Standard rules apply:
- The roll is: Governing Attribute + Arc Theory (+ Focus if applicable)
- Arc Theory dice are purchased from the Talent budget at character creation, or improved through Advancement at standard cost (Governing Attribute × 2 XP for a new Tradition at 1D; current value × 2 XP to improve)
- Maximum Tradition rating: 5D. Maximum Focus rating: 3D
- All three Expressions draw on the same Odd Talent pool
- Arc Theory is not available through Independent Study. Without either the Ashori lineage or a qualifying Profession, a character has no path to this tradition.
Governing Attribute
The governing Attribute is chosen at character creation and is permanent. This choice shapes how the tradition expresses across all three Expression categories; it is not expression-specific.
| Governing Attribute | Expression Character |
|---|---|
| Body | Raw output. Charge delivery is physical in quality, direct, forceful, felt in the body of the practitioner and the target alike. Discharge at range becomes a physical bolt; system interaction is brute activation; field effects have presence and pressure. |
| Wit | Precision. Charge delivery is calibrated, targeted, efficient, shaped to minimize collateral. Discharge is surgical; system interaction is controlled destruction; field effects can be localized to specific components or frequencies. |
Both are fully capable across all three Expressions. The choice determines how the capability manifests, not which applications are available.
Access
Ashori Lineage: Ashori begin with lineage-direct access to Arc Theory at 1D. This die does not come from the Talent generation budget. A Profession that additionally grants Arc Theory access provides the 2D affinity upgrade (bringing the Ashori to 2D) rather than stacking independently.
All other lineages: Access via Profession only. A character without the Ashori lineage and without a qualifying Profession cannot access this tradition regardless of XP invested. The biological substrate is not required, but the formal training pathway is.
Mechanics Summary
| Feature | Detail |
|---|---|
| Tradition | Arc Theory |
| Category | Force, directed electromagnetic output, system activation and disruption, sustained field generation |
| Governing Attribute | Body (raw output) or Wit (precision), chosen at creation, permanent |
| Roll | Body or Wit + Arc Theory (+ Focus) |
| Flux | Clear (first use per scene) / Overloaded (subsequent uses; Disadvantage) |
| Action Type | Primary Action (most applications); Free Action (minor Touch-range charge delivery) |
| Expressions | Discharge · Interface · Field |
| Foci | Conductive Strike, Systems Interface, Field Array |
| Lineage-direct | Ashori at 1D; all other lineages via Profession only |
| Backlash trigger | Roll while Overloaded + Wild Die shows 1 + total successes = 0 |
Threshold Scale
| Threshold | Scale of Effect |
|---|---|
| 1 | Minor; Touch range; a flicker, a spark, a small activation or brief disruption |
| 2 | Standard; single target or system at Close range; scene-relevant output |
| 3 | Significant; extended effect, resistant system, or multiple targets; Near range |
| 4 | Major; persistent field, cascade potential, or heavily shielded target |
| 5+ | Profound; station-scale disruption, simultaneous system failure, lasting structural effect |
Expressions
Discharge
The Current goes where you send it.
Discharge is the combat-facing and direct-output expression of Arc Theory, charge directed outward as a physical force, projected at range or delivered through conductive material. It is the expression that extends what the Ashori's biological perks already do (Touch-range damage, Close-range burst) into deliberate, repeatable, range-extended capability.
The damage type is Energy (Electrical). Targets with integrated electronics, cybernetic augmentation, or conductive materials in their composition may be additionally affected by Discharge applications; this is not a mechanical bonus by default but a fiction note that GMs should act on when relevant. Targets with electrical immunity (Ashori among them, and certain constructed beings) are unaffected by Discharge damage.
Directed Arc The practitioner sends a visible line of charge from their position to a target. The arc seeks the most conductive path available, which is not always the most direct.
- Threshold: Vs. target's Defense (attack roll)
- Range: Close to Near
- Duration: Instant
- Effect: Roll Governing Attribute + Arc Theory (+ Focus) vs. target's Defense. On hit, damage = total successes rolled. Damage type: Energy (Electrical).
- Notes: The arc is visible; it leaves scorch marks on surfaces it passes near. Free Action variant: Available at Threshold 1, Touch range, dealing 1 Electrical damage. Useful in close-quarters combat, as a demonstration, or to trigger electrically sensitive mechanisms without the practitioner being visibly at the console. Range extension to Far: Add 1 required success above the target's Defense. Scaling: Excess successes above Defense add 1 damage each, or impose the Hindered condition on the target until the end of their next Turn (2 excess required).
Conductive Arc The practitioner channels discharge through a conductive surface, metal deck plating, a railing, pooled liquid, a chain, rather than through air.
- Threshold: 2
- Range: Touch (to the conductor); affects all creatures in contact with the conductor within Close range of the practitioner's contact point
- Duration: Instant
- Effect: Each creature in contact with the conductor within Close range of the contact point makes a Body Save vs. Threshold 2 or takes damage equal to the practitioner's successes. Damage type: Energy (Electrical).
- Notes: Does not require line of sight to affected creatures, only to the conductive surface. Creatures with electrical immunity are unaffected. Targets wearing insulating equipment (vacuum suits with sealed soles, specific station gear) may be exempt at GM discretion. Scaling: 1 excess success extends reach along the conductor to Near range from the contact point; 1 excess success adds +1 damage to all affected targets.
Surge A maximized discharge delivered through direct physical contact, the practitioner dumps the full available charge into a single target or system.
- Threshold: 3
- Range: Touch
- Duration: Instant
- Effect: Against a creature: roll vs. Defense; on hit, damage = successes × 2; the target must additionally make a Body Save vs. Threshold 3 or become Stunned until the end of their next Turn. Against a system: functions as a high-output Interface application (equivalent to Controlled Overload) with the force of a Threshold 3 roll behind it.
- Notes: Surge depletes the practitioner's immediate charge reserve, Disadvantage on all Discharge applications until end of the scene. This is depletion, not a Condition; it stacks with the Overloaded Flux state if the practitioner is already there. Scaling: 1 excess success extends Stunned duration to the end of the target's second Turn; 2 excess successes increases the damage multiplier to successes × 3.
Interface
The system doesn't know the difference between your key and your Current.
Interface is the expression of Arc Theory that directly manipulates systems and infrastructure through electrical interaction. It extends the Ashori's biological diagnostic capacity from passive read-only sensing into active capability, charge delivered to a system to activate it, overload it, or induce effects through its conductive components.
Touch access is required for all Interface applications. This is not a Threshold requirement; it is a physics constraint. The practitioner's charge must reach the system through physical contact (their hand, a conductive tool they are holding, a surface in direct electrical contact with the target system). Applications that involve field induction rather than direct contact are handled in the Field Expression.
What Interface is not: programmatic control. Activating a locked console delivers charge, the system responds as it is designed to respond when powered or triggered. The practitioner does not choose what the system does; they choose whether it receives charge and in what quantity. What the system does with that charge is a function of its design, not the tradition. Practitioners who want to redirect a system's behavior rather than simply activate or destroy it require hacking tools and appropriate Talent rolls, the same as anyone else.
Activation The practitioner delivers charge sufficient to trigger a system's activation function, a locked door, a control panel, a powered-down terminal, a disabled weapon system.
- Threshold: 2 (standard system) / 3 (secured or shielded system) / 4 (system with active countermeasures)
- Range: Touch
- Duration: Instant
- Effect: The system's activation function triggers. What the system does on activation is determined by its programming, not the practitioner.
- Notes: Systems that require a specific access credential respond to delivered charge the same way they respond to a valid power signal. Failure means insufficient charge, the system may register an anomalous power event at GM discretion but is otherwise unchanged. Scaling: Excess successes allow selection among multiple activation functions the system already has, "open the door and disable the alarm" on 2 excess, for example. Excess successes are not programmatic control.
Controlled Overload The practitioner delivers a precise, calibrated charge to destroy a specific component within a system without cascading to adjacent systems, a power conduit severed, a sensor array burned out, a communications module destroyed.
- Threshold: 3
- Range: Touch
- Duration: Permanent until repaired
- Effect: The targeted component is non-functional until repaired. Surrounding systems are unaffected.
- Notes: This is the Wit-governed expression at its most precise. Body-governed practitioners can perform Controlled Overload, but with less surgical reliability, excess failures may extend damage to adjacent components at GM discretion. Knowledge requirement: the practitioner must either have specific knowledge of the target system's architecture or succeed on a Lore (Systems) roll (Threshold 2) as a Free Action immediately before the application. Scaling: Each excess success targets one additional component, still without cascade.
Cascade The practitioner deliberately induces an uncontrolled overload, charge delivered faster than the system's regulation architecture can manage, propagating along its power distribution pathways.
- Threshold: 4
- Range: Touch, the practitioner must be in physical contact with an active system that is drawing power; a completely depowered system cannot cascade
- Duration: Permanent until repaired
- Effect: The system and all systems directly connected to it in the same power circuit fail simultaneously. Connected systems may sustain varying levels of damage at GM discretion based on how heavily they were drawing power at the moment of cascade.
- Notes: This is a destructive application. Systems damaged by Cascade require significant repair. In a station environment, a Cascade in the wrong power circuit can affect life support, docking clamps, medical equipment, or other critical infrastructure. Practitioners are expected to understand what they are connected to before initiating one. Scaling: 2 excess successes allow the practitioner to specify which connected systems are affected and which are isolated, a Cascade that destroys the security grid but leaves life support running, for example.
Field
A sustained charge in the environment. What you do with it is a design decision.
Field is the expression of Arc Theory that generates and maintains a localized electromagnetic field rather than directing charge at a specific target. Field effects are sustained, they persist as long as the practitioner maintains them (or until the scene ends, at GM discretion for established fields). Maintaining a sustained Field does not cost an additional action, but the practitioner is considered to be maintaining it, significant disruption to their concentration, movement out of range, or falling Unconscious ends the effect.
Field and the Flux state: Establishing a Field is one Tradition use for Flux purposes. Maintaining an established Field through subsequent Turns does not count as additional uses, the Flux state is set when the Field is established. If the practitioner establishes a second, different Field effect while the first is maintained, that is an additional use and advances the Flux state.
Interference Field The practitioner generates a sustained EM field that disrupts electronic communication and sensor function within Close range of their position.
- Threshold: 2
- Range: Close, centered on the practitioner and moving with them
- Duration: Sustained
- Effect: Communications equipment within the field does not function. Electronic sensors (motion detectors, automated security cameras, network-connected monitoring systems) register false readings or go offline. Active station security AI managing affected sensors may flag the disruption within 1D3 Turns.
- Notes: Faction-hardened communications equipment (military-grade, encrypted-channel devices) require a Threshold 3 roll to establish the field against them. Non-electronic systems, mechanical locks, line-of-sight observation, biological senses, are entirely unaffected. The field is invisible to standard observation; practitioners of Arc Theory, Cybernetic Integration users with active sensing capabilities, and station systems with anomaly detection will recognize it as an active EM distortion. Scaling: 1 excess success extends the field radius to Near range; 1 excess success increases the Threshold required for hardened equipment to function within it by 1.
EM Shield The practitioner generates a sustained electromagnetic field that intercepts and dissipates incoming electrical charge, providing protection against energy-type attacks and environmental electrical hazards.
- Threshold: 2
- Range: Close (self and all allies within Close range)
- Duration: Sustained
- Effect: The practitioner and all allies at Close range gain Electrical Resistance 3, all Energy (Electrical) damage is reduced by 3 before applying to Health, minimum 0. Environmental electrical hazards (exposed conduits, electrified surfaces, station system discharge events) are similarly reduced.
- Notes: Does not stack with the Ashori lineage's inherent Electrical Resistance, an Ashori practitioner under EM Shield benefits only from the higher of the two values (which is typically the same, since both provide 3). The shield is not visible to unaided observation, it produces a slight distortion in very fine electronic sensors and is detectable by active Arc Theory practitioners who know what to look for. Scaling: 1 excess success increases Electrical Resistance to 4; 2 excess successes increases it to 5; 2 excess successes may instead extend coverage to Near range.
Induction The practitioner generates a precisely calibrated EM field sufficient to induce a current in a conductive target at Near range, without Touch contact. This is the Wit-governed tradition's furthest reach: charge direction at a distance, requiring the precision that Body-governed practitioners cannot reliably achieve at this scale.
- Threshold: 3
- Range: Near
- Duration: Sustained (field); Instant (effects of induced current)
- Effect: Choose one application per use: (1) Power delivery, charge a depleted power cell, activate a small system, or trickle-power a device; delivers charge equivalent to a brief controlled activation but not sustained power. (2) Environmental current, induce current through conductive environmental material at Near range; all creatures in contact with the conductor make a Body Save vs. Threshold 2 or suffer 1 Energy (Electrical) damage and the Hindered condition. (3) Disruption at distance, a cybernetic system on a target within Near range (requires line of sight) is disrupted; the target makes a Body Save vs. Threshold 3 or the targeted system goes offline for one Turn.
- Notes: Wit-governed practitioners only. Body-governed practitioners may attempt Induction at Disadvantage, the raw output orientation that makes Body-governed Discharge effective works against the precision Induction requires. Power delivery and environmental current cannot produce Controlled Overload or Cascade effects without Touch contact. Scaling: 1 excess success extends range to Far; 1 excess success increases environmental current damage to 2 (target is Stunned on a critical failure of the Body Save rather than Hindered).
Backlash
Backlash triggers when an Arc Theory roll is made while Overloaded, the Wild Die shows 1, and total successes equal 0. The specific effect depends on which Expression was in use at the time of the failed roll.
Discharge
| Threshold Attempted | Severity | Effect |
|---|---|---|
| Threshold 2 (Easy) | Minor | The discharge grounds through the practitioner, they take 1D3 Energy (Electrical) damage. Their own electrical resistance does not apply to internally grounded charge. |
| Threshold 3–4 (Standard/Difficult) | Moderate | The arc fires wild. The nearest creature at Close range (ally or enemy, GM determines ties) takes the full rolled damage as the discharge redirects to the most available conductor. The intended target is unaffected. |
| Threshold 5+ (Epic) | Severe | Uncontrolled release. The practitioner is Stunned until the end of their next Turn. Every electronic device and unshielded system within Near range is disrupted, powered down, offline, or sparking, for the remainder of the scene. Cybernetically augmented characters within Near range make a Body Save vs. Threshold 3 or suffer the Hindered condition. |
Interface
| Threshold Attempted | Severity | Effect |
|---|---|---|
| Threshold 2 (Easy) | Minor | The charge burns out more than intended, a different component than targeted is destroyed, or the targeted component's failure affects one adjacent system the practitioner did not intend. GM determines which component and what it controlled. |
| Threshold 3–4 (Standard/Difficult) | Moderate | Violent feedback. The system discharges back through the contact point, the practitioner takes Energy (Electrical) damage equal to the Threshold attempted, and the target system is destroyed (not just damaged). Any creature at Touch range of the practitioner takes 1 Energy (Electrical) damage from the discharge. |
| Threshold 5+ (Epic) | Severe | Full cascade without control. Every powered system within Near range of the practitioner fails simultaneously, the practitioner did not direct this, cannot direct it, and cannot stop it mid-event. All affected systems are destroyed and require full repair. The practitioner is Stunned until the end of their next Turn and takes 1D3 Energy (Electrical) damage from the backflow. |
Field
| Threshold Attempted | Severity | Effect |
|---|---|---|
| Threshold 2 (Easy) | Minor | The field collapses rather than establishing, its energy discharges inward. The practitioner suffers the Hindered condition until their next Short Rest. |
| Threshold 3–4 (Standard/Difficult) | Moderate | The field inverts. Rather than generating electrical resistance, it inverts the practitioner's relationship to incoming charge. The practitioner's Electrical Resistance drops to 0 until their next Short Rest, and they take +1 damage from all Energy (Electrical) sources during that period. |
| Threshold 5+ (Epic) | Severe | Uncontrolled EM pulse radiates outward in a Close-range burst. Every electronic device in range goes offline, comm equipment, active cybernetic systems, powered station fixtures. Creatures with active cybernetic augmentation at Close range must make a Body Save vs. Threshold 3 or suffer the Stunned condition. The practitioner is Stunned until the end of their next Turn. The pulse is unmistakable to anyone in range. |
Foci
Conductive Strike (Discharge Focus) Developed through extended practice with contact-delivery applications, typically with access to an Ashori training partner or mentor who can work with the practitioner on the contact-delivery instincts the Focus formalizes. Non-Ashori practitioners can develop Conductive Strike; it typically requires more deliberate effort to build the embodied instincts that Ashori carry biologically.
- Benefit: Add Focus dice to Discharge Expression rolls when the application involves physical contact or close-range delivery, Touch to Close range applications, Surge, and Conductive Arc initiated through a hand-held surface. Does not apply to ranged Directed Arc at Near or Far.
- Form: Embodied technique, the integration of contact-delivery instincts with formal tradition training. No physical item required. A practitioner who loses use of their hands temporarily loses access to this Focus.
Systems Interface (Interface Focus) A specialized conductive tool, an interface probe, a calibrated conductive gauntlet, or a custom modification to standard engineering tools, that extends and stabilizes charge delivery for Interface applications.
- Benefit: Add Focus dice to Activation, Controlled Overload, and Cascade applications. Additionally, the practitioner may make a Lore (Systems) roll as a Free Action (Threshold 2) immediately before an Interface application to identify unfamiliar system architecture, satisfying the knowledge requirement for Controlled Overload without a separate action.
- Form: A physical conductive tool. Can be lost, confiscated, or destroyed; losing it removes Focus access until a replacement is acquired. A practitioner without their Interface tool is working the tradition bare, capable, but without the precision enhancement the tool provides. Acquisition cost: Restricted tier (AX.GAT.09).
Field Array (Field Focus) A field emitter array integrated into a vest, harness, or station suit modification that distributes the field-generation load across multiple emitter points, reducing the cognitive demand of field maintenance.
- Benefit: Add Focus dice to Interference Field, EM Shield, and Induction applications. Additionally, maintaining an established Field effect no longer requires the practitioner's sustained attention, a Field established with this Focus persists for one full scene without concentration maintenance. The practitioner may move, act, and use other Expressions without disrupting an established Field. One unattended Field may be active at a time.
- Form: A physical emitter array worn or integrated into the practitioner's gear. Can be lost or destroyed; losing it removes the sustained maintenance benefit until a replacement is acquired. Acquisition cost: Restricted tier (AX.GAT.09).
Access and Cross-Lineage Notes
Ashori practitioners carry the tradition as a formalization of biological inheritance. The line between the lineage perks (The Current, Arc Discharge) and the tradition is blurred in fiction and clear in mechanics: the perks are always available; the tradition is subject to Flux. In practice, Ashori often find that the tradition's Clear-state use feels continuous with their biological function, the moment it shifts to Overloaded is the moment it begins to feel like something different from the Current they grew up with.
Ashori using the tradition in professional contexts (as engineers, in Survey Corps roles) carry the friction that the Ashori community has with how their Current is framed. To most employers, there is no distinction between the biological function and the formal tradition; it is all "the Ashori electrical thing." Practitioners who have developed the tradition formally and know the difference tend to have strong feelings about that conflation.
Non-Ashori practitioners are learning to generate and direct charge through discipline, working from the outside in, building a capability that Ashori practitioners have had since childhood. They are not at a mechanical disadvantage for this. The tradition functions identically regardless of biological origin.
What non-Ashori practitioners do not have is the biological perks. They have no inherent Touch-range discharge, no Electrical Resistance, no passive diagnostic sensing. The tradition gives them Arc Theory's formal Expression capability; it does not give them the Ashori lineage. Practitioners without the biological baseline sometimes develop more technical orientations toward the tradition (Systems Interface Focus is proportionally more common among non-Ashori practitioners) because they came to it through engineering frameworks rather than through embodied practice.
The boundary with Cybernetic Integration: Both Arc Theory and Cybernetic Integration (Form, AX.GAT.08.05) interact with electronic systems and cybernetic components. The boundary between them is defined by direction and purpose:
| Question | Arc Theory | Cybernetic Integration |
|---|---|---|
| Direction | Projects outward into the environment | Transforms and integrates inward |
| What it does to cybernetics | Disrupts or overloads them | Enhances or integrates them |
| System interaction scope | Activates/destroys via Touch; disrupts at range | Routes through own hardware to data layer |
| Self-modification | No | Core function |
Edge case ruling: A cybernetically augmented target struck by an Arc Theory Discharge application or caught in an Interface backlash takes the effect normally, their integrated architecture is the conductor, not a shield. Cybernetic Integration's defensive capabilities may provide mitigation if specifically designed for it; this is resolved at GM discretion based on what augmentations the target has.
A practitioner who has both traditions is unusual and notable, the combination of outward electrical projection (Arc Theory) and inward cybernetic integration (Cybernetic Integration) represents a significant tradition investment and a distinctive capability profile. The traditions do not mechanically conflict. They represent different orientations toward the same underlying electromagnetic reality.
Station context: Arc Theory practitioners are not uncommon aboard the Terminal, the tradition has a natural home in the engineering-adjacent labor market and the Survey Corps, both of which work in environments where electrical and EM interaction with systems is routine. Station Authority is aware of the tradition and monitors its practitioners to the same degree it monitors other traditions: documentation requirements, periodic credentialing, and increased scrutiny for practitioners operating in restricted sectors.
The tradition's relationship to station infrastructure means that high-level practitioners represent a genuine security concern for Station Authority and the Corporate Bloc alike. A practitioner capable of Cascade has the theoretical capacity to damage critical systems. Most practitioners never use Cascade. Station Authority's interest in monitoring the tradition is not predicated on most practitioners behaving badly; it is predicated on what a small number of exceptions could do.