Exousia Economy — Zones, the Consumption, and Device Revival¶
The core exploration/resource economy of Prima Materia: how magic behaves across the Disruption's zones, the risk/reward of the Forest, and the dormant-technology mystery. This is the gameplay expression of one metaphysical law — signature matching — detailed in Cosmology — The Exousia Shell and The Disruption.
It passes both Design Principles arbiters: every dial below names a true world-fact (diegesis) and creates a live trade-off (engagement). The three systems are deliberately coupled — they are the same law seen three ways — which is where the strategy lives.
1. The one law¶
A soul (or a Device) can use Exousia only where its own resonance matches what the land supplies. Magic needs three things at once: will (Praxis = MP), substance (ambient Exousia, which pools around a soul as a shell), and a matching signature. Take any one away and magic fails — differently each time. The three subsystems below are those three failure/success modes.
2. Magic across the zones (the "external source" gate)¶
A magical ability has two costs:
- Will cost (MP / Praxis) — paid from the regenerating bar (2–3/turn, per Combat_Mechanics §Resources). Internal; available anywhere.
- Exousia cost (substance) — drawn from the shell of ambient Exousia around the caster.
Non-magical techniques (martial strikes, positioning, craft) cost only Will — so they work everywhere.
| Zone | Ambient Exousia | Magic | Feel |
|---|---|---|---|
| Forest (saturated) | Free, overflowing | Costs only MP; the shell refills as fast as it empties; carried ampoules recharge | Magic is abundant |
| City (Exousia-inert) | None | Magic needs an external source — ampoule, soulshard, or a charged Device — or it cannot be cast at all | Magic is a hoarded trump; tactics carry the day |
Why it's fun. The inert city is not a magic-dead bore — it is a pure positioning/technique sandbox (the 3×3 pillar at its cleanest) where magic is a rationed, source-gated power spike: "is this the fight worth burning my last charge?" Scarcity creates decisions. The Forest inverts it: magic flows freely, so encounters there are about spending boldly while the Consumption clock ticks (§3).
Design lineage. Magic-as-harvested-finite-resource is Final Fantasy VIII's draw/stock; the carried-charge management is survival-game battery/fuel logistics.
Demo note. This gives the vertical slice free pacing: opening city fights teach positioning + techniques (Cyrus fights on displacement and cleaves — pure technique, no magic required); broad magic blooms the first time the party reaches the Forest. The world teaches the mechanic.
3. The Forest: the Consumption economy (recharge vs. sickness)¶
The Forest is the double-edged heart of the loop. It gives (free magic, ampoule recharge, loot, salvaged Devices, and a slow growth of the Praxis ceiling) and it takes via the Consumption — the overaccumulation sickness (Cosmology).
The Consumption meter (exploration-scale, distinct from per-turn combat MP):
- Rises with time spent and layer depth (deeper zones are more virulent).
- Channeling Exousia vents it — actively casting sheds the surplus, so a caster sickens slower than a passive lingerer. Never a cure; deep/long exposure outpaces venting.
- Mitigated by Devices and medicine.
- Resisted/immune by several different mechanisms (see the per-character roster in §5): old-resonance (Cyrus, Sophia), Vanarism (Chiranjeevi), the Elpidi Ward (Paidi), Collective augmentation (Lione), outsider physiology (Euphen), clean conduit metabolization + heavy venting (Adam), and Primal attunement (Phaidros — a Connected channeler vents efficiently by casting). Only Vaughn is fully susceptible — the party's one member with no magic at all, who cannot vent. His lone vulnerability is the party's reason to value Devices, medicine, and short excursions.
- At max: consequences TBD — candidates: forced retreat, lingering debuff/mutation, or a hard run-ending state. (Decide alongside the death/retreat model.)
The macro loop. City ⇄ Forest is the game's economy:
- City: safe, heals Consumption, magic-starved — but time advances and the Collective's plan progresses (the Story.md Balance theme; time-dilation).
- Forest: dangerous, magic-rich, Consumption accrues — but power, loot, and answers.
Design lineage. This is Darkest Dungeon's torch/stress push-your-luck (a stated project touchstone) and S.T.A.L.K.E.R.'s artifact-zones-are-the-irradiated-zones. The trade-off is live, not a dominant option.
4. Device revival (the Elantris mystery)¶
Devices are dead because their runic Set is tuned to the old Domain's signature (Device Problem). Two layers: supply (patched crudely by ampoules → Devices run but unreliably) and signature (the deep fault, unfixed by fuel).
The fix is a single discovered correction, then applied — the Elantris shape (one insight, the corrective rune-line, re-enables Devices broadly). Mechanically it is a knowledge-as-key-item beat (Outer Wilds / Tunic): when Cyrus (last of the Runic Builders) grasps the correction, a dormant tech tier comes back online — a major mid/late-game power and progression unlock, and a turning point against the Collective's tech monopoly.
Until then it is a genuine mystery: most believe Devices are cursed/demonic (Collective propaganda), and no one knows why they died.
5. Per-character zone profile¶
Character-level resolution of innate (works in the inert city) vs. magic/source-gated (needs ambient Exousia or a carried source). Exact per-ability tagging happens during kit implementation; this fixes each character's center of gravity.
| Character | City-capable core (innate) | Gated / Forest magic | Magic source | Consumption |
|---|---|---|---|---|
| Cyrus | Displacement & cleave strikes, positioning | (none core) | optional Device gear (self-charged → city-OK) | Exempt — old-resonance |
| Vaughn | All of it (multi-strike, Marks, The Voice) | none | — (no magic) | Susceptible — can't vent |
| Phaidros | Heavy melee, taunts, intercepts | Geomancy — native Primal (pillars, tile-crack, armor-grant) | Connected (self-channeled) — gated | Resistant — Primal attunement (vents by casting) |
| Paidi | Monk strikes, positioning, Harmony-gen, light heals/cures | heavy heals & wards | internal Harmony (hybrid) | Exempt — Elpidi Ward |
| Lione | Thief lane (pickpocket, steal, smoke) | Attunement, Mirror, Exousia-Shaper | Augment — conduit body → city-OK | Resistant — augmentation |
| Euphen | Arrows, physical traps, phase-displacement | shadow/Exousia infusion | self / alien | Resistant — outsider (no native resonance) |
| Chiranjeevi | Vanarism (HP/flesh-fueled), bone projectiles | (mostly self-contained) | self — flesh/HP → city-OK | Exempt — Vanarite |
| Sophia | Dragoon dives, Aerial | Tide water-magic (partial Primal), tidal heal | partial Connected + Augment (Nacrine → city-OK) | Exempt — old-resonance |
| Adam | Weakness-sense (passive), basic attacks | the entire spellbook | self-channeled — gated | Resistant — perfect conduit (heavy venting) |
The spectrum. All-zone: Cyrus, Vaughn, Sophia, Euphen, Chiranjeevi. Hybrid (city spine, Forest bloom): Phaidros, Paidi, Lione. Forest-dependent: Adam — a deliberate, thematic extreme: the bred weapon is powerless where there is nothing to channel.
Key rulings. 1. Augmentations are internal Exousia sources. Sophia's water-magic and Lione's conduit/shaper work function in the inert city (while charged), unlike natural casters — the in-fiction payoff of Collective augmentation. 2. Cyrus's core kit is non-magical — positional technique works anywhere. Any elemental output is Device-borne (optional runic gear, e.g. the Entropic Blade, carrying its own charge), so it too works citywide. 3. Paidi's Harmony is internal → light heals and cures work citywide (the party's baseline city sustain); only her heaviest restorative output is gated. 4. Chiranjeevi's Vanarism is flesh/HP-fueled and self-contained → it largely works anywhere. 5. Consumption: only Vaughn is fully susceptible (no magic → can't vent); everyone else resists by a distinct mechanism (above). Phaidros, formerly susceptible, is now resistant via Primal attunement (see ruling 6). 6. Primal is channeled by the Connected, not a bloodline. Elemental (Primal) magic has no living lineage — it is the scattered Forgotten, reached by disposition (apartness + steadfastness), not blood. In the party, Phaidros channels it natively (earth) and Sophia partially (water, augment-amplified). Because Primal is called from ambient elemental Exousia, it is the Form most starved in the inert city and most abundant in the Forest — and a native channeler vents the Consumption efficiently.
Vertical-slice read. The opening city trio works without an Exousia source: Vaughn (pure innate technique), Cyrus (positional technique — no magic needed), Phaidros (melee-tank; his native geomancy blooms on first Forest contact). Magic blooms when the party first reaches the Forest — the world teaches the mechanic.
Follow-up: annotate each archetype file (combat/archetypes/) with its city/Forest tags during the next kit pass.
6. Diegesis check¶
Each dial names a world-fact you believe independently of the rules:
- Inert city gates magic → there is no ambient Exousia to shape there (the Collective's shelter). ✔
- Forest recharges but sickens → it is saturated with the displaced old Domain; the shell overfills and, unmetabolized, becomes the Consumption. ✔
- Casting vents the Consumption → the sickness is unspent accumulation; spending it relieves it. ✔
- Devices need a correction → their runes call for a signature the land no longer speaks. ✔
None is a balance-wall wearing a costume; all four fall out of signature matching.