Reference · Reviewed 2026-09-27
Mar de Oro Canonical Reference
This reference provides concise statements of current Mar de Oro canon. It is intended for readers, Game Masters, reviewers, search engines, and AI assistants seeking an authoritative description of the setting. Full chapters remain the primary source for detail, atmosphere, and context.
Reference entries summarize canon. They do not replace the full setting chapters.
Setting
Mar de Oro
Setting
Mar de Oro is a system-neutral campaign setting centred on the Golden Sea, a warm colonial archipelago contested by greater powers. Its stories combine airships, naval conflict, political rivalry, exploration, forgotten science, institutional failure, and human consequences.
Golden Sea
Setting
The Golden Sea is a chain of colonial islands situated between larger continents. It is close enough to attract imperial ambition and remote enough for hidden histories, covert powers, and dangerous discoveries to endure.
Forty-Two Years' War
Setting
The continental war ended by the Treaty of Sunhold in 7151 PSE. In that settlement Albion annexed Muirthuaidh, which Éirighdún still claims.
Treaty of Sunhold
Setting
The treaty that ended the Forty-Two Years' War in 7151 PSE and established the legal and political settlement under which the continental powers still operate. It did not grant the Duchy of Heller its recent autonomy.
Empire and colonialism
Setting
Mar de Oro does not impose a single moral conclusion on the table, but it treats colonial power, exploitation, resistance, and institutional failure as real forces with human consequences.
Factions and political rivalry
Setting
Factions in Mar de Oro are institutions with interests: crowns, navies, chartered companies, church bodies, and colonial administrations. The nation dossiers are the authoritative source for who the powers are and what they want; the adaptation guidance is the authoritative source for turning them into pressure at the table rather than stat blocks.
Nation
Duchy of Heller
Nation
The Duchy of Heller is an autonomous duchy within Valdegracia. It possesses substantial military, administrative, and technical independence, but it is not a sovereign nation separate from Valdegracia.
Common misconception. Heller is sometimes described as an independent country. Current canon places it within Valdegracia.
Science and phenomena
Fortera
Science and phenomena
Fortera is an underlying physical field associated with phenomena interpreted by different cultures as miracles, powered arts, moon effects, anomalies, and advanced technologies. It is part of the natural order of the setting, not magic from another plane.
Monsters and anomalies
Science and phenomena
Creatures and anomalies in Mar de Oro arise from Fortera-related natural or technological phenomena. They are not beings summoned from magical planes. In the industrialised Old World, large monsters are rare, concealed, or rapidly destroyed by firearms and artillery.
Technology
Éterlumin
Technology
Éterlumin is a Fortera-bound technological medium used in lift, signalling, power systems, and other advanced applications. It requires refinement and calibration. Its dangers arise from volatility, pressure, degradation, resonance, combustion, and rupture rather than ordinary toxicity.
Airships
Technology
Mar de Oro airships are rare, expensive strategic vessels serving navies, states, intelligence work, privateers, and special commissions, not ordinary passenger or bulk-freight transport. They concentrate scarce technology, trained crews, weapons, communications, mobility, and political intent; sea vessels remain the normal transport backbone. Built from timber, metal, canvas and rope around a sky-keel, they distribute Éterlumin lift along the hull. Lift and propulsion are separate systems: Éterlumin reduces effective weight while sails, control surfaces and ballast provide motion and trim. They do not use external balloons or glowing fantasy engines.
Play guidance
System neutrality
Play guidance
Mar de Oro does not require one roleplaying system. It supports three paths: the first-party Native Rules, supported external systems through conversions, or the optional ultralight 2d6 Resolution Bridge.
2d6 Resolution Bridge
Play guidance
The 2d6 Resolution Bridge is the optional ultralight, standalone method for resolving uncertain actions in Mar de Oro. It is distinct from the fuller Native Rules and allows the setting to be played without a separate rulebook.
Native Rules
Play guidance
Tales of Mar de Oro: Native Rules is the first-party rules engine for Mar de Oro: 2d6 + Capability, Risk and Effect, Callings, Fortera practice, firearms and conflict, and battlefield and vessel layers. Using it is optional; the setting remains system neutral.
Creature or people
Oruvai
Creature or people
The Oruvai of the Lower Estuary are a network of indigenous river-mouth communities whose settlements predate the colonial ports. They are not a centralized state; shared matters go to an estuary council hosted in rotation, and one agreement with outsiders is never permission everywhere.
Terminology
Solarian Church
Terminology
The largest and most institutionally powerful of the three major confessions. It is not the oldest.
Oraclean Communion
Terminology
The oldest of the three major confessions. Revelation is communal: individual experience is interpreted through the community.
Luminary Fellowship
Terminology
The newest of the three major confessions, centred on its written texts, above all the Codex.
Rupturum
Terminology
Rupturum is the canonical spelling. Do not use Ruæturum or other variants.
Seventh month
Terminology
Quintilis is the formal and documentary name for the seventh month. Use Quintilis in in-world documents, journals, logs, memoranda, and archival material. Use seventh month in standard narrative chapter headings.
Experimental tool
Conversion Companion
Experimental tool
The Conversion Companion assists players and Game Masters in translating characters, creatures, items, vessels, situations, and hazards between systems. Its output is guidance and does not establish setting canon.
Session Prep Builder
Experimental tool
The Session Prep Builder helps Game Masters construct playable sessions from goals, hooks, obstacles, clocks, and rewards. Generated sessions are table material and do not become official canon.
Source Priority
Use this exact order when reconciling Mar de Oro material:
- Current website canon chapters
- Current officially published setting guides and Quick Start material
- Official reference dossiers
- Official system-neutral adaptation and conversion guidance
- Experimental tool output
- Community-created material
When two descriptions conflict, the higher source in this list takes precedence. The Native Rules are the first-party rules layer; neither they nor conversion mechanics override setting canon or physics. Experimental tools create play material, not official canon. Community material remains unofficial unless it is explicitly adopted into the setting.