Use Mar de Oro with any ruleset. Begin with the fiction, choose the mechanics second.
Overview
Mar de Oro is a system-neutral setting.
Its nations, factions, technologies, conflicts, mysteries, characters, and campaign structures do not depend on classes, levels, spell lists, fixed statistics, or any particular method of rolling dice.
The setting was originally developed and played using Dungeons & Dragons Fifth Edition because that was the system familiar to the group at the time. Its D&D 5e conversion is therefore the most extensively tested mechanical implementation currently available.
This does not make D&D 5e the official or required Mar de Oro system.
In retrospect, Blades in the Dark may provide an especially natural fit for several of the setting's central concerns, including crew-centred campaigns, faction pressure, difficult choices, accumulating consequences, and fiction-first action. The group was not familiar with Blades in the Dark when the original campaign was played, so its conversion should be treated as adaptation guidance rather than an equally tested implementation.
The purpose of this chapter is not to declare one system correct. It is to help you preserve the identity of Mar de Oro in whichever ruleset your group chooses.
System-neutral does not mean mechanically empty.
It means the setting explains:
Mar de Oro provides:
Your chosen system determines how those elements are resolved.
A capability might become a skill bonus, proficiency, action rating, aspect, background, approach, move, permission, or dice pool.
A vessel problem might become a damage track, progress clock, extended test, challenge sequence, or series of linked scenes.
The mechanical expression may change.
The fictional meaning should remain stable.
The Ladder
Any character, creature, vessel, institution, hazard, or situation can be adapted by answering six questions.
| Step | Question | Result |
|---|---|---|
| 1. Fictional Role | What does it do in the story? | Ally, threat, authority, obstacle, resource, mystery |
| 2. Capability | How competent is it? | Familiar, Trained, Expert, Master |
| 3. Scale | What can it meaningfully affect? | Personal, Crew, Vessel, Faction, Regional |
| 4. Pressure | Why must the characters act? | Time, pursuit, suspicion, degradation, obligation |
| 5. Consequences | What changes when things go badly? | Harm, delay, exposure, damage, debt, escalation |
| 6. Mechanical Expression | How does the chosen system represent it? | Roll, clock, condition, resource, move, challenge |
Answer these questions in order.
Statistics chosen before fictional purpose may produce a functional game mechanic, but they may not produce an accurate representation of Mar de Oro.
Step One
Determine what the subject does in the story.
Common roles include:
A Valdegracian marine, for example, is not defined first by an armour class, attack value, or damage die.
The marine is a disciplined professional soldier who:
The chosen ruleset should express those qualities.
A merchant company might be a source of employment, an institutional rival, or a campaign-level threat.
An airship might be transportation, a mobile refuge, a military asset, a political symbol, or a failing objective.
A priest might be an ally, an authority, a keeper of forbidden knowledge, or someone trapped between doctrine and conscience.
The same setting element may fulfil different roles in different campaigns.
Step Two
Mar de Oro uses four capability ranks:
These ranks describe fictional competence.
They do not correspond to fixed bonuses, target numbers, character levels, dice sizes, or automatic success.
The character understands the fundamentals and can assist competently.
A Familiar practitioner may:
They may struggle when working alone, under severe pressure, or without suitable equipment.
The character can perform the work professionally under ordinary conditions.
A Trained practitioner may:
Most professional soldiers, sailors, engineers, investigators, physicians, navigators, and officials are Trained in the capabilities central to their occupation.
The character can handle difficult cases, supervise others, recognise unusual problems, and teach the discipline.
An Expert practitioner may:
Experts are trusted with substantial responsibilities.
The character is among the finest practitioners in the region.
A Master practitioner may:
Mastery should remain rare and significant.
A character without relevant training may still attempt an action when the fiction permits it.
However, they may:
Capability influences what a character can reasonably attempt and how safely they can attempt it.
It does not guarantee success.
Preparation, equipment, information, relationships, authority, and circumstances remain important.
| Capability | Fictional Meaning | Common Mechanical Expression |
|---|---|---|
| No Relevant Training | May attempt the task only when circumstances permit | Reduced effect, higher risk, disadvantage, restricted options |
| Familiar | Understands the basics and can assist | Basic proficiency, limited permission, small bonus, one die |
| Trained | Reliable professional competence | Standard proficiency, normal action rating, competent baseline |
| Expert | Handles unusual problems and leads others | Strong bonus, enhanced effect, specialised actions |
| Master | Rare regional excellence | Exceptional permission, signature ability, major effect |
These are examples rather than universal numerical values.
Always calibrate them to the chosen system.
Step Three
Scale describes the level at which an action, threat, organisation, or consequence operates.
Capability and scale are separate.
An Expert engineer may be able to repair one airship but cannot personally resolve a regional shortage of calibrated Éterlumin without political support, infrastructure, and resources.
Personal scale concerns one person, creature, room, mechanism, or immediate confrontation.
Crew scale concerns a small group, patrol, household, shipboard team, or local operation.
Vessel scale concerns an airship, fortification, military company, large expedition, refinery, or major industrial installation.
Faction scale concerns a government, church, company, fleet, noble house, intelligence service, military command, or organised movement.
Regional scale concerns a war, widespread disaster, political crisis, economic collapse, or major failure of infrastructure.
A lower-scale action does not normally defeat a higher-scale threat by itself.
Characters may instead:
A personal action may begin a faction-level transformation, but connected actions, allies, and sustained effort will usually be required.
Scale should make institutions and regional conflicts feel substantial without making individual characters irrelevant.
| Starting Scale | Higher-Scale Objective | Useful Leverage |
|---|---|---|
| Personal | Influence a crew | Leadership, evidence, reputation, sacrifice |
| Crew | Disable a vessel | Boarding, sabotage, command, engineering |
| Vessel | Pressure a faction | Blockade, public victory, captured intelligence |
| Faction | Change a region | Alliances, trade control, military action, legitimacy |
| Personal | Harm a faction | Exposure, testimony, sabotage, political leverage |
A lower-scale action can matter greatly when it targets the right vulnerability.
Step Four
Pressure is the force that makes a situation urgent, dangerous, or difficult.
It explains why the characters cannot continue indefinitely without the circumstances changing.
Common pressures include:
Pressure should be visible in the fiction.
Players should understand what is worsening and why action matters.
Your chosen system may represent pressure through:
Pressure should not exist only as hidden arithmetic.
It should shape decisions.
| Pressure | Warning Signs | Possible Consequences |
|---|---|---|
| Éterlumin degradation | Uneven lift, pressure fluctuation, calibration drift | Reduced service life, lost altitude, instability, rupture |
| Political suspicion | Questions, surveillance, restricted access | Exposure, arrest, loss of standing, diplomatic conflict |
| Pursuit | Sightings, signals, closing distance | Interception, route change, separation, capture |
| Crew strain | Fatigue, arguments, abandoned stations | Reduced effectiveness, mistakes, disobedience, injury |
| Resource shortage | Rationing, failing equipment, delayed repairs | Lost capability, debt, dangerous improvisation |
| Fortera instability | Resonance, tremors, failed calibration | Backlash, injury, disruption, unwanted attention |
| Relationship pressure | Demands, silence, divided loyalties | Broken trust, obligation, betrayal, withdrawal of aid |
| Public unrest | Rumours, demonstrations, refusals, violence | Loss of authority, riots, intervention, political collapse |
| Military escalation | Patrols, mobilisation, ultimatums | Battle, blockade, conscription, diplomatic rupture |
This table is intended as inspiration.
It is not a mandatory random table.
Step Five
Before resolving an uncertain action, establish what may change if the characters fail, hesitate, or accept a dangerous bargain.
Useful consequences include:
Failure should normally change the situation rather than stop the story.
A failed investigation may uncover the clue while alerting the enemy.
A failed repair may restore partial function while damaging another system.
A failed negotiation may secure cooperation in exchange for an obligation.
A failed escape may move the characters to safety while leaving evidence behind.
A failed boarding action may place the characters aboard the enemy vessel while separating them from their allies.
Consequences should emerge from the attempted action.
They should not feel arbitrary or disconnected from the situation.
A GM may find it useful to think of consequences in three broad levels.
| Level | Use When | Examples |
|---|---|---|
| Minor | The situation worsens but remains controlled | Lost time, spent supplies, increased suspicion |
| Serious | The characters lose position, safety, or support | Injury, damaged equipment, broken trust, capture risk |
| Severe | The situation changes dramatically | Vessel failure, death, faction rupture, public exposure |
The chosen system may already define degrees of failure or consequence.
Use its procedures where appropriate.
Step Six
Once the fictional role, capability, scale, pressure, and consequences are clear, select the appropriate procedure from the chosen ruleset.
This may involve:
Mar de Oro does not require one particular resolution method.
Use the procedure that best represents the action and suits the pacing of the scene.
Do not call for a roll when:
Resolve uncertainty mechanically when the outcome is uncertain and its consequences matter.
Difficulty should emerge from the fictional circumstances rather than from a universal conversion number.
Consider:
A task may be routine for one character and extremely difficult for another.
An Expert engineer with suitable tools may diagnose an ordinary lift-system fault quickly.
The same engineer may struggle when:
Difficulty should reflect the complete situation, not only the technical complexity of the task.
Use the ladder only for elements likely to matter during the session.
Do not assign statistics to every named character, building, vessel, or organisation.
Prepare what the players are likely to interact with.
Leave the rest in fictional terms until it becomes relevant.
When players attempt something unexpected:
Review the adaptation before the next session.
Ask:
Adjust the mechanics without changing the fictional definition.
A Valdegracian marine should remain disciplined and dangerous in formation even if the exact statistics change.
Translate each Mar de Oro capability into the closest equivalent offered by the chosen system.
One capability may affect several mechanical areas.
A direct one-to-one conversion is not required.
Command may become:
Investigation may become:
Engineering may become:
Fencing may become:
Navigation may become:
Preserve what the character can meaningfully accomplish in the fiction.
Then express that competence through the chosen ruleset.
Bonds and Burdens remain important in every system.
They should influence decisions, create opportunities, and produce consequences.
They should never become decorative text.
Bonds connect characters to:
A Bond may provide:
Burdens create obligations, vulnerabilities, and unresolved pressures.
A Burden may involve:
A ruleset may represent Bonds and Burdens through:
Whatever mechanical form they take, they should return to play.
| Type | Prompt |
|---|---|
| Bond | Who would you risk your position to protect? |
| Bond | Which vessel, community, or institution feels like home? |
| Bond | Who trusts you more than they should? |
| Burden | What obligation cannot be ignored? |
| Burden | Who would suffer if your secret became public? |
| Burden | What promise has become dangerous to keep? |
Define threats through behaviour before assigning statistics.
Record:
Then select or create an appropriate mechanical profile.
Institutions should not be represented as oversized individual enemies.
Define:
A faction may act through:
Characters usually affect a faction by creating leverage rather than reducing a single pool of health.
Useful forms of leverage include:
Fortera should not be reduced to a generic catalogue of supernatural effects.
It is defined through:
A Fortera effect should establish:
A ruleset may express Fortera through:
The mechanical form may change.
The need for discipline and control should remain.
A practitioner may force an effect beyond safe or ordinary limits.
Overdraw may provide:
Overdraw should always create meaningful risk.
Possible consequences include:
Use the chosen system's equivalent of:
Overdraw should feel powerful, costly, and exceptional.
| Benefit | Possible Cost |
|---|---|
| Greater range | Unwanted resonance |
| Increased intensity | Physical strain or injury |
| Faster execution | Loss of precision |
| Larger scale | Damage to nearby systems |
| Temporary stability | Greater instability afterward |
| Impossible effect | Lasting consequence or exposure |
Éterlumin is a volatile gaseous resource used in transport, industry, and airship lift systems.
Its defining limitation is inevitable degradation.
Controlled Fortera reactivation and calibration can slow that degradation.
They cannot stop it permanently.
No grade remains stable forever, including material kept in sealed containers.
Éterlumin quality should be understood through:
It should not be reduced to a simple purity rating.
A batch or system may be described as:
These are descriptive conditions rather than mandatory mechanical categories.
A chosen system may represent them through:
Éterlumin is not inherently toxic.
Its principal dangers are:
Its danger should arise from its physical and resonant behaviour, not from generic poisoning.
| Condition | Fictional Meaning | Typical Effects |
|---|---|---|
| Well Calibrated | Stable operation and long remaining service life | Reliable output, low immediate pressure |
| Serviceable | Safe for normal use | Routine operation, expected degradation |
| Declining | Performance is beginning to deteriorate | Reduced efficiency, increased maintenance |
| Unstable | Calibration is failing | Irregular output, increased risk |
| Near Rupture | Pressure and instability are approaching catastrophic levels | Severe restrictions, immediate danger |
| Spent | No longer capable of useful service | Loss of output, replacement required |
Airships should be adapted through operational role rather than direct numerical comparison.
Define:
A vessel may have different capability ranks in different areas.
For example:
This is usually more useful than assigning one overall vessel rating.
Where the chosen system supports them, use four principal vessel areas:
Damage should alter what the vessel can do in the fiction.
Hull damage may cause:
Rigging or Lift damage may cause:
Crew losses may cause:
Damage or degradation may cause:
| Area | Light Consequence | Serious Consequence | Critical Consequence |
|---|---|---|---|
| Hull | Damaged plating or weapons | Structural breach | Hull failure |
| Rigging or Lift | Reduced control | Loss of altitude or manoeuvrability | Uncontrolled descent |
| Crew | Fatigue or minor casualties | Abandoned stations | Command collapse |
| Éterlumin Reserve | Reduced endurance | Instability and loss of lift | Rupture or complete failure |
Airship and naval engagements may use four range bands.
| Range | Typical Activity |
|---|---|
| Distant | Observation, pursuit, evasion, signalling, long-range fire |
| Closing | Manoeuvring, interception, identifying weaknesses, preparing boarding parties |
| Engaged | Serious fire, disabling attacks, contested positioning |
| Grappled | Direct boarding, close weapons, fighting for decks and access points |
Translate these bands into the distance, zones, movement rules, or positioning procedures used by the chosen system.
Characters should influence vessel conflict through meaningful responsibilities.
Possible roles include:
Airship conflict should not reduce player characters to passive passengers while the vessel resolves the battle around them.
Every major phase should present decisions that matter.
Complex repairs, investigations, diplomatic efforts, journeys, and long operations may be represented through:
An extended problem should establish:
Failed attempts should normally introduce new problems rather than erase all progress.
Examples include:
Extended problems should create movement, escalation, and difficult choices.
Serious injuries should matter beyond the immediate loss of health.
A lasting injury may affect:
Injuries do not need to remove a character from play.
They may instead change:
Use the chosen system's rules for:
Three extended examples showing the ladder applied to a vessel, a faction investigation, and a Fortera crisis.
Interactive
Use this worksheet when translating a character, threat, vessel, institution, hazard, location, or campaign element.
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What is being adapted?
What purpose does it serve in the story?
What does it want, require, or attempt to protect?
What makes it effective, influential, or dangerous?
What weaknesses, dependencies, limitations, or contradictions can be discovered?
What makes the situation urgent?
What may change if the characters fail, hesitate, or accept a cost?
Which statistics, rolls, moves, clocks, conditions, resources, or procedures will represent it?
What may require adjustment after play?
Whatever system is used, retain the setting's core pressures.
These principles are more important to the identity of Mar de Oro than any individual statistic.
The following procedures were originally published as part of the System Conversion Notes. They are preserved here because they apply across multiple rulesets.
When the fiction, the dice, and the rules seem to disagree, the group is making a hard call. Handle these calls out loud, briefly, and in the open. Restate what the character is trying to accomplish, name the pressure and consequence already on the table, and confirm the intended stakes before committing to a ruling.
Prefer rulings that honour the fiction and the established capability of the character. Prefer consequences that keep the situation moving over consequences that erase progress. When a ruling turns out to have been wrong, correct it at the next natural pause rather than reversing rolls mid-scene.
The powered arts, including Fortera practice and its disciplined traditions, are part of the setting rather than a system layer. Run them by asking what the practitioner is trying to change in the world, what the local field can safely support, and what a deliberate push beyond that safe limit would cost.
Ordinary use remains within what local replenishment, personal discipline, and present conditions can safely support. An Overdraw is a deliberate attempt to exceed that safe capacity and must provide an exceptional benefit while also imposing Fortera strain, local instability, or another meaningful consequence.
Named-system pages link back to this section using the label System-neutral table procedures.
Mar de Oro was originally developed and played using Dungeons & Dragons Fifth Edition because it was the system familiar to the group at the time.
The D&D 5e conversion is therefore the setting's most extensively tested mechanical implementation.
The System-Neutral Adaptation Ladder provides a shared foundation for translating Mar de Oro into other rulesets.
It preserves the setting's fictional identity, but it does not guarantee mechanical balance in every system.
Each group should calibrate:
No single rules engine is the official Mar de Oro system.
Choose a Ruleset
D&D 5e supports familiar heroic adventure, structured character advancement, and recognisable tactical encounters. It is currently the most extensively tested Mar de Oro conversion.
These mechanics are optional. They do not define the setting itself.
Pathfinder 2e supports detailed tactical encounters, structured character options, and precise mechanical distinctions. Its Mar de Oro material should be treated as adaptation guidance unless a section is specifically identified as playtested.
Conversion page in preparation.
Blades in the Dark may be an especially natural fit for Mar de Oro because of its emphasis on crew identity, faction relationships, accumulating pressure, position and consequence, difficult bargains, long-term projects, and fiction-first action.
Treated as adaptation guidance unless a section is specifically identified as playtested. Conversion page in preparation.
Groups that prefer a lightweight standalone method may instead use the optional Mar de Oro 2d6 Resolution Bridge. The setting remains the same. Only the method of resolving uncertainty changes.
Other Systems. Other rulesets may be used by translating capabilities, scale, pressure, Bonds, Burdens, vessel roles, Éterlumin conditions, Fortera strain, faction influence, and consequences. The setting remains the same. Only the method of resolving uncertainty changes.