Wednesday, April 8, 2026

OSR Commentary Adapting C1: The Hidden Shrine of Tamoachan To The Barrows & Borderlands Rpg

 


Adapting the classic C1: The Hidden Shrine of Tamoachan to the Barrows & Borderlands (B&B) framework requires shifting the focus from standard dungeon crawling to a high-stakes, survival-horror "extraction" crawl. This blog post picks right up from Adapting X2 Castle Amber (Chateau d' Amberville) By Tom Moldvay For Barrows & Borderlands Rpg




In B&B, the primary antagonist isn't just the monsters—it’s the Poisonous Gas and the ticking clock of your party’s resources.


### The Core Hook: The Suffocation Mechanic

In B&B, environmental hazards are lethal. As soon as the players fall into the ruins, they are affected by the Miasma of the Sunless Shrine.

  • The Clock: Every 10 minutes (one Dungeon Turn) of exploration, players must tick off 1 Ration or Torch to represent the extra effort of breathing/moving through the thick dust.

  • The Penalty: If the party stops for a Long Rest, every character must make a Vigor Save. On a failure, they gain the Fatigued condition, reducing their maximum Grit until they reach fresh air.


### Converting Key Encounters

Barrows & Borderlands thrives on "Weird Fantasy" tropes. Here is how to reskin the iconic Tamoachan threats:

Original ElementB&B AdaptationMechanical Twist
The Giant SlugThe Slime-Crusted HorrorActs as a "Terrain Hazard." Its trail forces an Agility Save or the character is Stuck.
The Vampire (Zotzilaha)The Hemomancer WraithInstead of level drain, it drains Grit directly. If Grit hits 0, the player becomes a Thrall.
The DoppelgangerThe Echo-ShifterIt doesn't just look like a PC; it copies the last Ability the PC used against it.
The Gas TrapsThe Blight VentsThese deal direct Inventory Damage. Instead of HP, the gas rots 1d4 random items in the backpack.

### The "Borderlands" Twist: Loot and Relics

Since B&B emphasizes the value of "The Haul," the Olman treasures should be more than just gold.

  • The Mirror of Itzpapalotl: In B&B, this acts as a cursed focus. It allows a caster to double their spell range, but every use requires a Sanity Check.

  • The Jade Mask: This functions as a "High-Tier Helm." It grants immunity to the shrine's poisonous gas but prevents the wearer from speaking or casting spells with verbal components.


### Navigation & Hazard Levels

To maintain the B&B "Meatgrinder" feel, divide the shrine into three distinct Hazard Zones:

  1. The Lower Chambers (The Crawl): Focus on Vigor and Agility. Heavy on pit traps and collapsing ceilings.

  2. The Middle Tier (The Ritual): Focus on Wits and Lore. This is where the environmental puzzles and "The Centaur" reside.

  3. The Upper Tier (The Breach): Focus on Combat and Speed. The gas is thickest here; players must find the exit before their Gear Slots are depleted by rot and exhaustion.


Design Note: Use the B&B Reaction Table for the various guardians (like the Giant Crayfish). Not everything in Tamoachan wants to kill the players immediately; some might be willing to trade "Safe Air" locations for the party’s precious supplies.

Gemini said

In Barrows & Borderlands, guardians aren't just bags of hit points; they are atmospheric hurdles that test a party’s resources, sanity, and tactical positioning. To fit the "Borderlands" feel, these Olman guardians should feel like ancient, semi-sentient bio-mechanical or spirit-bound constructs.

Here are the primary guardians of Tamoachan adapted with B&B mechanics:


### 1. The Teotl-Amoxtli (The Tome Guardian)

Originally a giant crayfish, in the B&B version, this is a massive, chitinous horror fused with obsidian shards, guarding the sunken bridge.

  • Hazard Level: High (Physical)

  • Key Attribute: Armor 4 (Obsidian Shell).

  • The Threat: Its claws don't just deal damage; they have the Sunder quality. On a successful hit, the player must sacrifice 1 Defense Item (Shield or Armor) or take double Grit damage.

  • The Twist: It is bioluminescent. If killed, its internal fluids can be harvested to create 3 Durable Torches that burn underwater and in gas.


### 2. The Zotzilaha Vampire (The Bat God’s Avatar)

Instead of a traditional vampire, this is a desiccated, leathery humanoid suspended in a glass vat of preservative "God-Blood."

  • Hazard Level: Extreme (Supernatural)

  • The Draining Gaze: Anyone making eye contact must pass a Spirit Save. Failure results in the Weakened condition—all Physical checks are at a disadvantage until the player consumes a full Ration.

  • Echo-Flight: It does not walk; it blurs between locations. Melee attacks against it suffer a -2 penalty unless the room is illuminated by more than one light source.

  • The Loot: The Heart of Zotzilaha. Can be crushed to instantly restore all Grit to the party, but inflicts a Permanent Scaring on the user's soul.


### 3. The Nahual (The Jaguar-Man)

The classic shapeshifter of the shrine, re-imagined as a "Shadow-Stalker" that haunts the party through the ventilation shafts.

  • Hazard Level: Medium (Stealth/Ambush)

  • Stalking Mechanic: The Nahual does not attack head-on. Every time the party rolls a "1" on an Exploration check, the Nahual strikes the person at the back of the marching order and vanishes.

  • Prowess: It ignores the first 2 points of damage from non-silvered weapons.

  • Weakness: It is terrified of True Fire. A torch held high keeps it at bay, but using a torch in the gas-filled lower levels risks an explosion.


### 4. The Kulkulkan Construct (The Feathered Sentinel)

A mechanical serpent made of gold, jade, and feathered silk, coiled around the central pillar of the upper tiers.

  • Hazard Level: High (Environmental)

  • The Coiling Constriction: Instead of biting, it wraps around a target. The target is Restrained and loses 1d6 Grit per turn from crushing force.

  • Jade Scales: The construct is immune to Poison and Bleed effects.

  • Tactical Solution: The construct is powered by a large gemstone in its forehead. A character can attempt a Wits Check to jam the mechanism with a crowbar or tool, bypassing the fight entirely.


### Guardian Stat Block Template (B&B Style)

GuardianGritSaves (V/A/W/S)Special Ability
Obsidian Horror2215 / 8 / 5 / 10Sunder: Destroys gear on a Crit.
Bat Avatar188 / 14 / 16 / 15Lifesteal: Heals 1d4 on hit.
Shadow Jaguar1210 / 18 / 12 / 8Vanish: Disappears after attacking.
Jade Serpent2516 / 12 / 8 / 5Heavy: Cannot be pushed or tripped.

### Management of "The Haul"

In B&B, these guardians are often standing on top of Relics. When a guardian is defeated, roll on the Ancient Olman Loot Table:

  1. Macuahuitl of Woe: A wooden sword embedded with obsidian. Deals +2 damage but breaks (is removed from inventory) on a natural 1.

  2. Chacmool Basin: A stone bowl that purifies any liquid placed inside, turning it into Clean Water (1 Usage).

  3. Quetzal Cloak: Grants the wearer a +4 bonus to Agility Saves involving jumping or falling.

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.