Mar de Oro Canonical Reference

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.

• Start here →
• About the 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.

• World atlas →
• Nations of the Golden Sea →

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.

• Nations of the Golden Sea →
• About the setting →

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.

• Duchy of Heller dossier →
• Nations index →

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.

• Fortera chapter →
• Éterlumin chapter →

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.

• Fortera chapter →
• World atlas →

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.

• Éterlumin chapter →
• Fortera chapter →

Mar de Oro airships are Age of Sail vessels adapted for flight through internal lift systems, Éterlumin engineering, specialised hull structures, sails, control surfaces, and disciplined crews. They do not use external balloons or glowing fantasy engines.

• Éterlumin chapter →
• World atlas →

Mar de Oro does not require one roleplaying system. Play using your preferred TTRPG system, or use the included optional 2d6 Resolution Bridge. No separate rulebook is required when using the Bridge.

• System-neutral adaptation →
• System conversions →

The 2d6 Resolution Bridge is an optional lightweight method for resolving uncertain actions in Mar de Oro. It allows the setting to be played without a separate roleplaying rulebook.

• 2d6 Bridge →

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.

• Conversion Companion →

The Session Wizard helps Game Masters construct playable sessions from goals, hooks, obstacles, clocks, and rewards. Generated sessions are table material and do not become official canon.

• Session Wizard →
• Game Master Toolkit →

Rupturum is the canonical spelling. Do not use Ruæturum or other variants.

• Éterlumin chapter →

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.

• Calendar →