Mar de Oro for D&D 5e

Conversion status

The original Mar de Oro campaign was developed and played using D&D Fifth Edition because it was the ruleset familiar to the group. It is therefore the most extensively tested Mar de Oro implementation. Individual optional mechanics may still require adjustment for party tier and campaign style.

System-agnostic table procedures (Hard Calls at the Table and Running the Powered Arts) live in the System-Agnostic Adaptation chapter because they apply across multiple rulesets.

The Calling Table

Use the Calling table as a menu of familiar 5e chassis for each Mar de Oro Calling. It identifies mechanical starting points; it does not automatically choose a final class or subclass for a player. Capabilities, Bonds, Burdens, personal history, and crew role should guide the final build.

Powered Arts by Temperament

The Powered Arts by Temperament table below suggests mechanical starting points based on how the character approaches disciplined practice. Fortera is the underlying field and disciplined practice used within the setting. References to D&D classes, spell structures, traditions, or resources are mechanical conversion tools rather than literal explanations of how Fortera works.

D&D 5e Notes

Fortera Approach: Mechanical Starting Points

These are mechanical starting points, not literal statements about how Fortera works in the setting. Fortera is not generic magic.

Capability translation

Translate the Familiar / Trained / Expert / Master ladder to 5e proficiency, expertise, and ability-score progressions in the System-Agnostic Adaptation chapter. On this page, treat proficient as Trained, and expertise or class-feature specialisation as Expert or Master depending on tier.

Bonds and Burdens

Represent Bonds through Inspiration triggers, background features, and NPC allies with mechanical support. Represent Burdens through recurring complications, contested resources, and features that introduce cost when they are used at pressure.

Crunch Pack (5e): Fortera Overdraw

Fortera is the underlying field and disciplined practice used within the setting. References to D&D classes, spell structures, traditions, or resources are mechanical conversion tools rather than literal explanations of how Fortera works.

Ordinary Fortera use remains within what local replenishment, personal discipline, and present conditions can safely support. Overdraw is a deliberate attempt to exceed that safe capacity.

An Overdraw must provide an exceptional benefit while also imposing Fortera strain, local instability, or another meaningful consequence.

Possible exceptional benefits may include:

• Greater effect.
• Increased scale.
• Extended duration.
• Greater range.
• Acting through interference.
• Completing an otherwise impossible working.

Choose one Overdraw procedure for the campaign. Do not apply both the Simple Overdraw cost and the Crunch Pack Overdraw cost to the same working unless the GM deliberately intends an unusually severe consequence.

Simple Overdraw procedure

A lightweight option: when a character pushes beyond safe capacity, severe Fortera strain may impose one level of Exhaustion in addition to the fictional consequence. Use when the group prefers minimal bookkeeping.

Crunch Pack Overdraw procedure

For this optional mechanic, capacity means the highest effect, scale, or intensity the character can safely produce under the current circumstances. Each tier over capacity represents one additional step beyond that safe limit. The GM and player should establish the intended tier before the roll.

The published Constitution save formula, tiers over capacity, strain dice, ripple multipliers, settling periods, and severity categories are preserved as originally released and are not rebalanced on this pass. Fortera strain is not Éterlumin poisoning.

Éterlumin hazards

Contained, non-active Éterlumin may be transported as controlled cargo, but it continues to degrade over time. Hazards arise when pressure, calibration loss, resonance, heat, active fire, structural damage, or containment failure make the gas unstable. Active Éterlumin is flammable, so existing fire and explosion procedures may be used when ignition, rupture, or active combustion is genuinely present. Proximity alone is not poison exposure and should not automatically require a Constitution save.

Éterlumin is gaseous and inevitably degrades. Controlled Fortera recalibration can slow degradation. Recalibration cannot reverse the age of Éterlumin or permanently stabilise it. No grade remains stable forever, including in sealed containers. Grades describe degradation rate, remaining service life, and calibration quality rather than purity alone.

Extended challenges

Use a segmented clock or skill-challenge frame from the System-Agnostic Adaptation chapter, then express successes as ability checks or saves appropriate to the fictional obstacle. Failures introduce complications rather than removing progress.

Crunch Pack (5e): Airship & Naval Combat Statistics

Track vessels by role and by these systems, not by a single HP pool:

• Hull
• Rigging or Lift
• Weapons
• Crew
• Command and Communication
• Éterlumin Reserve, when relevant

Vessel Attacks

Each vessel makes one attack on its turn unless a specific vessel trait explicitly states otherwise. The Broadside value in the table represents the total damage of that single vessel attack. It is not rolled once per cannon, gun deck, battery, or listed weapon.

A vessel may describe the attack as a full broadside, concentrated battery, bow attack, or another appropriate firing solution, but it still resolves as the vessel's single attack.

Emergency support vessels may perform emergency recalibration, slow further degradation, stabilise containment, transfer serviceable reserve, replace damaged components, and restore controlled operation. They may not recharge degraded Éterlumin like a battery, reverse the age of Éterlumin, remove all degradation, or permanently stabilise Éterlumin. Do not describe any vessel as a “rechargeable battery” or say it “recharges Éterlumin systems.”

Crunch Pack (5e): Targeting Subsystems

The previously published subsystem percentages and numerical values are preserved as originally released. The subsystem previously labelled “Engines / lift” is renamed Rigging or Lift: controls lift, sail handling, steering, altitude control, and manoeuvring as appropriate to the vessel. Airship movement and lift are not automatically the same system.

Éterlumin Reserve is tracked separately from subsystem hit points. It represents remaining usable service, calibration condition, containment integrity, and operational availability. Damage, Overdraw, failed recalibration, or containment problems may reduce the reserve without functioning like ordinary hull damage.

The Mar de Oro Crunch Pack (5e): Volley Fire

Playtested optional mechanic

This Volley Fire procedure was tested in play against both individual characters and military formations.

Volley Fire coordinates multiple ranged attackers into a single resolved action against an area or a formation. The published damage dice, damage caps, Dexterity save formula, Wisdom save formula, suppression rules, morale procedure, and preparation and reloading requirements are preserved as originally released and are not rebalanced on this pass.

When used against individual characters, each affected target resolves the required saves. When a military formation is represented as a single game unit, resolve the volley against that formation according to the formation procedure being used.

The damage pool represents one coordinated formation volley, not one separate attack for every musket.