Further Thoughts On Combining Warriors of the Red Planet and 13 Parsercs Rpg - The Barsoomian Way Part II

 

Merging 13 Parsecs (a solo-play toolkit for sci-fi exploration) with Warriors of the Red Planet (a Sword & Planet OSR game) creates a gritty, atmospheric "John Carter meets Rogue-like" experience. This blog post picks right up from Combining Warriors of the Red Planet and 13 Parsercs Rpg - The Barsoomian Way

Since 13 Parsecs is designed for a "used future" aesthetic and Warriors of the Red Planet (WRP) is focused on pulp planetary fantasy, you’ll be playing in a setting where high-tech salvage meets ancient, dying civilizations.

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1. The Core Mechanical Bridge

The primary challenge is reconciling the Health/Combat systems.

• Hit Dice vs. Hits: 13 Parsecs often uses a "Hits" or low-HP system. Stick to the WRP Hit Dice and Armor Class for combat to keep the pulp "hero" feel alive.

• The 13-Day Clock: In 13 Parsecs, you have a limited time to pay off debt or reach a goal. In a Red Planet setting, rename this the Oxygen/Water/Rad-Cell Clock. If it hits zero, your air or hydration fails in the wastes.

Converting Character Stats

WRP Attribute	13 Parsecs Equivalent	Use Case
Strength	Prowess	Melee, lifting, brute force.
Dexterity	Coordination	Piloting sky-ships, dodging traps.
Constitution	Endurance	Resisting thirst, radiation, or exhaustion.
Mental (Int/Wis)	Logic / Intuition	Deciphering ancient Martian tech.

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2. Setting the Scene: The "Dying World" Hex-Crawl

Use the 13 Parsecs procedural generation tables to map out the Martian wastes instead of deep space.

• Sector Generation: Instead of star systems, each "sector" is a City-State, Ruined Spire, or Silt Sea.

• The Ship: Your "Ship" in 13 Parsecs becomes your Sky-Galleon or Thark Beast-Train. Upgrades apply to its speed across the desert and its mounted radium cannons.

• The Goal: You aren't just looking for scrap; you're looking for Life-Water or Atmosphere Plant Parts to save your dying enclave.

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3. Adapting the Tools

The beauty of 13 Parsecs is its Oracle and Encounter tables. Here is how to reskin them for the Red Planet:

• Encounters: When the toolkit says "Space Pirates," read Red Martian Raiders. When it says "Xeno-Monster," read Great White Ape.

• Loot & Salvage: Instead of "Circuitry" or "Reactor Parts," you find Psychic Crystals, Orichalcum Scraps, or Radium Vials.

• Social Interactions: Use the WRP Reaction Table alongside the 13 Parsecs "Motivations" table to see if the Barsoomian princess you just rescued actually wants your help or is leading you into a trap.

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4. The "Science-Fantasy" Math

If you encounter ancient machinery or need to calculate the trajectory of a falling moon, keep the math consistent with WRP's OSR roots.

For example, if you are jury-rigging a power cell and need to determine the energy output ($E$) based on remaining Radium mass ($m$) and a decay constant ($k$):

$$E = m \cdot e^{-kt}$$

(In-game, just roll under your Intelligence/Logic score, but the flavor text should feel like high-concept pulp science!)

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5. Gameplay Loop

1. Departure: Leave the safety of a domed city (The Hub).

2. Travel: Use 13 Parsecs travel rolls. Each "Jump" is a day’s trek across the crimson sands.

3. Discovery: Use the Oracle to determine what you find (A crashed scout ship? A nest of Thoats?).

4. Combat/Conflict: Resolve using Warriors of the Red Planet rules for that fast-paced, lethal OSR feel.

5. Return: Sell your loot, recover your HP, and tick down your 13-Day Doom Clock.

To capture the "high-crunch" procedural feel of 13 Parsecs and the planetary romance of Warriors of the Red Planet, this d100 table is designed with "Sub-Tables" and mechanical hooks.

This ensures that a single roll provides both narrative flavor and a direct mechanical challenge for your OSR-style campaign.

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The Red Planet d100 Master Encounter Table

d100	Result Type	Encounter Description	Mechanical Hook (WRP / 13 Parsecs)
01-05	The Void-Call	A psychic echo from an ancient, dying Moon-Mind.	Save vs. Mental or suffer 1 level of Sorrow/Stress.
06-15	Thark War-Band	2d6 Green Martians on Thoats, scouting for water.	Reaction Roll -4 if you have visible water or radium.
16-25	Atmosphere Leak	A pocket of "Thin Air" or a ruptured ancient pipe.	13-Day Clock ticks down 1 extra step due to exhaustion.
26-35	Radium Scavengers	Red Martian drifters stripping a crashed Sky-Galleon.	Logic Check to salvage 1d6 Radium Vials.
36-45	Great White Ape	A starving, four-armed behemoth in a ruined archway.	Surprise Check. High AC and 3 attacks per round.
46-55	The Silt-Shifter	A massive, burrowing crustacean mimicking a sand dune.	Treat as a Hazard. Coordination check to avoid ship damage.
56-65	Ancient Relic	A pulsating Orichalcum obelisk covered in Oghamic script.	Roll on the Specialized Tech Table (see below).
66-75	Dust Storm	A "Static-Red" storm that fries electronics and optics.	All ranged attacks at -4; movement reduced to 1/4.
76-85	Imperial Scout	A sleek, chrome-plated flyer from a distant High-City.	Intuition Check to hide before they spot your "Ship."
86-95	The Water-Witch	A rogue psychic offering "Life-Water" for a high price.	Cost: 1 permanent HP or a Rare Salvage item.
96-00	The Glass-Sea Ghost	A phantom ship from Mars’ lush, watery past.	Event: Gain a temporary "Past-Life" Trait or Perk.

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Specialized Tech Sub-Table (d10)

If you roll 46-55 or Salvage a Relic, roll a d10 to see what the "Crunch" is:

1. Gravity Bracers: +2 to Coordination/Dexterity for 1 hour.

2. Neural-Whip: Target must Save vs. Paralysis or be stunned for 1d4 rounds.

3. Solar-Still: Converts 1 unit of Radium into 1 week of Water.

4. Psionic-Emitter: Can cast Telepathy once per day (Mental Check required).

5. Radium Flare: Blinds all biological eyes in a 50ft radius.

6. Thoat-Whistle: Summons a wild mount, but has a 10% chance to attract a predator.

7. Crystal Lens: Grants +2 to Logic checks when deciphering ancient maps.

8. Void-Suit Patch: Instantly repairs 1 "Hit" of hull damage to a Sky-Galleon.

9. Oghamic Tablet: Teaches one random "Science-Fantasy" Spell or Maneuver.

10. The Dead-Hand: A cybernetic graft. Roll d100 on your Graft Table to install.

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Environmental Hazard Logic

For procedural travel across the Red Planet, use a Depletion Die for your essential resources (Water/Radium).

If your group travels through a High-Radiation Zone, calculate the dosage ($D$) relative to the time ($t$) and the intensity constant of the sector ($R$):

$$D = \int_{0}^{t} R(x) \, dx$$

Pro-Tip: If the total $D$ exceeds your Endurance/Constitution, you take 1d6 permanent attribute damage until you reach a High-City Med-Bay.

Combining Warriors of the Red Planet and 13 Parsercs Rpg - The Barsoomian Way

Integrating Warriors of the Red Planet with Thirteen Parsecs (often referred to as 13P) is a very natural fit, as both games are rooted in the "Old School" design philosophy.

While they use different core engines, their shared DNA makes them highly compatible for a "Sword & Planet" campaign.

System Compatibility

• Engine Foundations: Warriors of the Red Planet is a traditional OSR (Old School Revival) game based on the original fantasy RPG rules. Thirteen Parsecs uses the O.G.R.E.S. engine (Old-school Generic Roleplaying Engine System).

• The "Feel": Both systems prioritize high adventure, ruling-over-rules, and a lean mechanical footprint. Because Thirteen Parsecs is designed to be a "New Class of Old School," it shares the same bounded accuracy and power scales as Warriors of the Red Planet.

How to Play Them Together

Since Thirteen Parsecs is a toolkit for any sci-fi subgenre, you can use it to "crunch up" the more minimalist Warriors setting:

• Character Archetypes: You can easily swap classes. For example, use the Mystic Knight or Psychic from 13P to replace or augment the Mentalist in Warriors.

• Starship & Tech Rules: Warriors is lighter on technical vehicle rules. You can use the robust Starship Creation and Combat rules from Thirteen Parsecs to handle the high-flying airships of Mars or Venus without breaking the math.

• Conversion: Since both use standard attributes (Strength, Dexterity, etc.) and similar Armor Class/Target Number logic, you can usually port monsters and NPCs between them with zero math. If a Martian creature in Warriors has a 4 HD (Hit Dice), it will function effectively as a Level 4 threat in 13P.

Why Combine Them?

If you find the "Original Fantasy" bones of Warriors a bit too restrictive for high-tech encounters, Thirteen Parsecs provides the Skill System and Career Training that can give your planetary heroes more specialized utility outside of combat.

Since both games are built on the foundational "Old School" six-attribute chassis, you can port characters with almost zero math. The primary goal is to map the flavor of Warriors of the Red Planet (WRP) onto the slightly more granular 13 Parsecs (13P) engine.

1. Attribute Mapping

Both systems use the standard range (3-18). You can port your Strength, Dexterity, Constitution, Intelligence, Wisdom, and Charisma directly.

• Saving Throws: 13P uses a unified "Save" based on the O.G.R.E.S. engine. Use the character's Level + Attribute Modifier to hit a Target Number (usually 15 for difficult tasks).

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2. Class Conversion Table

Because 13P is a toolkit, you can "build" a WRP class using its archetypes and career paths.

WRP Class	13P Archetype	Suggested 13P Career
Fighting Man	Soldier	Mercenary or Gladiator
Scoundrel	Operative	Smuggler or Scout
Scientist	Technician	Engineer or Medic
Mentalist	Psychic	Mystic or Telepath

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3. Integrating Features

To make the character feel truly "Red Planet" while using 13P rules, apply these three mechanical tweaks:

• The "Barsoomian" Perk: Every character from WRP should receive a +1 bonus to all Athletics and Leaping checks in 13P to represent the lower gravity of a dying world.

• Weapon Scaling: Use 13P's weapon damage (e.g., 1d6 for light, 1d8 for medium). Treat WRP Radium Pistols as 13P Blaster Pistols, but keep the WRP "Misfit" rule (exploding on a natural 1) to maintain the high-stakes feel of ancient tech.

• Mentalism vs. Psionics: Use the 13P Strain system for Mentalists. Instead of WRP's "Daily Uses," allow the character to push their powers by taking 1d4 non-lethal damage per level of the effect used beyond their safe limit.

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4. Health and Armor

• Hit Points: You can keep your WRP Hit Points as-is. Both systems scale similarly per level.

• Armor Class: 13P typically uses Ascending AC. If your WRP character has a Descending AC of 5, their 13P Armor Rating is 15.

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Warriors of The Red Planet Rpg & Lieut. Gullivar Jones: His Vacation by English writer Edwin Lester Arnold For An Old Mars Campaign

Mars is a massively dangerous place to dungeon crawl & adventuring down in the ruins. This blog post picks up from this blog post. 

So we've been working with Warriors of the Red Planet and taking advantage of the multi WoRP races and PC classes. This is a great system to run full on post apocalyptic rpg campaigns. 

To this end I've been rereading Lieut. Gullivar Jones: His Vacation by English writer Edwin Lester Arnold, & this book has numerous elements that perhaps inspired Edgar Rice Burroughs 'A Princess of Mars'. 

Lieut. Gullivar Jones: His Vacation was published in 1905 & 'A Princess of Mars' was published in 1917. 

Is there a way of including both Gullivar Jones's Mars  & John Carter's Barsoom together in one campaign setting. According GULLIVER JONES ON BARSOOM?  by Den Valdron in ERBzine issue 1403 there's a ton of reasons why Gulliver Jones adventures took place in the Arctic region of Barsoom. 

The Mars of Gullivar Jones is highly dangerous place because it's essentially a prehistoric micro cosm of 'the Mars of yesteryear'. Sure you've got the Hither & Thither peoples with a relatively stable culture comparable to the Eloi & the Morlocks of HG Wells Time Machine novel. But there are other peoples, creatures, etc. which the author doesn't get deeply into. I have to admit that it was a bit slow going at times with the Edwin Lester Arnold going into far more detail about the alien plants then the creatures and monsters. Does this actually line up with evolutionary traits of ancient Mars?! What I'am I talking about?! 

Does Lieut. Gullivar Jones: His Vacation's fixation on the plant life point up a truth that we've found within Clark Aston Smith's Mars cycle. The simple evolutionary truth that the animal life on Mars is highly aggressive and multi limbed  for a reason. That reason is the fact that the plant life is highly evolved to kill animal life in a wide variety of creative ways. 
Think about it. Mars even when it was green is a very 'plant eats animal' based world. This Mars belongs to the first cycle of the planet when it was dominated by plant based life, gods, and even horrors.  We know this because Clark Ashton Smith goes hard into this with his Mars Cycle: 

• Dweller in the Gulf, The  (1933)
• Mnemoka (1955) Fragment
• Vaults of Yoh-Vombis, The  (1931)
• Vulthoom  (1935)
• Seedling of Mars or The Planet Entity  [plot by - E M Johnson] (1931)[An alternative background to the proceeding 4 stories]

What does this mean for Edgar Rice Burroughs material?! Quite a bit for the DM whose linking all of these stories together for their Warriors of the Red Planet campaign. Edgar Rice Burroughs's Plant Men from The Gods of  Mars by  Edgar  Rice Burroughs are hold overs from this time period gardened and tended by the Therns and their religion of manipulation. This ecological manipulation goes deeply into the lands of the Hither & Thither peoples. Extending deeply into the dungeons & ruins of the Martian underworld. We'll go down into the Martian underworld, the Therns, and the dungeon ecology of Mars next time. 

Warriors of The Red Planet & Clark Aston Smith's The Vaults of Yoh-Vombis (1931) - For An Old Mars Campaign

'There were eight of us, professional archaeologists with more or less terrene and interplanetary experience, who set forth with native guides from Ignarh, the commercial metropolis of Mars, to inspect that ancient, aeon-deserted city. Allan Octave, our official leader, held his primacy by virtue of knowing more about Martian archaeology than any other Terrestrial on the planet; and others of the party, such as William Harper and Jonas Halgren, had been associated with him in many of his previous researches. I, Rodney Severn, was more of a newcomer, having spent but a few months on Mars; and the greater part of my own ultra-terrene delvings had been confined to Venus.'

'I had often heard of Yoh-Vombis, in a vague and legendary sort of manner, and never at first hand. Even the ubiquitous Octave had never seen it. Builded by an extinct people whose history has been lost in the latter, decadent eras of the planet, it remains a dim and fascinating riddle whose solution has never been approached . . . and which, I trust, may endure forevermore unsolved by man. Certainly I hope that no one will ever follow in our steps . . . .'

• Clark Aston Smith's Vaults of Yoh-Vombis, The (1931)

 There's something right outta of the gate of the Clark Aston Smith's Vaults of Yoh-Vombis, The (1931)that reeks of the alieness of Mars. A certain morbidness  air that hangs right in the opening paragraphs. These are a crew of adventurers under the guise of archaeologists who are plumbing the depths of a Mars that humanity barely understands.  This is an old and very dangerous world hoary with age, horror, and alien Lovecraftian gods dwelling in its underworld.

This Mars belongs to the first cycle of the planet when it was dominated by plant based life, gods, and even horrors. This is related in the 1933 story by Clark Aston Smith in which  these stories are set on the same Mars - that of the Aihais and their predecessors the Yorhis. These two peoples belong to the next cycle when Mars crests into the Barsoomian cycle. This makes it easy to move this campaign into a Warriors of the Red Planet rpg campaign. 

But the alien plant cycle won't be denied because the Aihais and their predecessors the Yorhis are hoarders of ancient forbidden secrets sequestered away in lost valleys of a grim and highly dangerous Mars. For Warriors of the Red Planet campaign 'This is a world where mankind has made his mark & then stumbled into the fires of his own nuclear fall from grace. There are space ports here and there, a few human city states but the Martian races have re emerged on Mars from hidden valleys & scattered colonies across the face of Mars. There are ancient Lovecraftian horrors & gods that rule as they have for billions of years scattered in certain countries across the face of this world. This is world where the sword is king & you need to keep your radium side arm handy. Mutants, ancient evils, and worse await you in the red night.' The Blackgate blog covers this with The Fantasy Cycles of Clark Aston Smith Part IV with the following; "  The current inhabitants of Smith's Mars call themselves Aihais and have barrel chests, multi-articulated arms, high flaring ears, and pit-like nostrils. The best remembered of the dead civilizations, the Yorhi, have physical similarities to the Aihai but left behind sinister ruins and legends of their passing." 

Humans are only now starting to unearth and explore these forbidden ruins. And for the sake of the human race we'd better hope they don't uncover the wrong dungeon. 

Clark Aston Smith's Mars in his Martian cycle is a dark and forbidding place where the human race is trespassing on a world that humanity barely understands at all. Could Barsoom fit into this?! Why not we've got planet men who are highly dangerous and one of the last things that some poor 2000 year old Red Martian is likely too see.