An ancient abomination born of forbidden ritual sleeps beneath Vermouth’s Great Cathedral — fed by a fanatical high priest who calls it a god of purification and a warlock who has grafted himself into its living flesh — and unless the heroes descend into its digestive depths and end it, the city above will be consumed from within.
Welcome to “The Maw of the Cube” 5E adventure! Within these pages, you’ll discover everything necessary to embark on this thrilling quest, complete with detailed descriptions of locations, encounters, NPCs and stat blocks, maps, and handouts.
This adventure also features a versatile and scalable system, allowing Game Masters to easily adjust the difficulty and complexity of encounters to suit their players’ preferences and skill levels. Whether you have a party of advanced players or beginners, you can tailor the challenges to ensure an exciting and engaging experience for everyone involved. The scalable system guides modifying creature statistics, making it simple to customize the adventure to fit your party’s level.
In “The Maw of the Cube,” a party of 3-5 characters (levels 5-7) arrives in plague-stricken Vermouth, where robed zealots drag the sick beneath the Great Cathedral for “cleansing” — never to return. The culprit is the Maw, a colossal sentient ooze created by the long-dead Ossuary Pact and dormant for generations beneath the city’s foundations. High Priest Gellert Vorne discovered it and mistook it for a divine being, feeding it plague victims. Meanwhile, Malakar the Hungerer, an exiled warlock, forged a pact with the awakening creature and has since fused himself into its living tissue, guiding its hunger toward conquest. The heroes must navigate the city’s chaos, descend through three levels of increasingly organic dungeon, and face a final confrontation at the Maw’s pulsing Heart — where destroy, bind, or be consumed are the only paths forward. The adventure is divided into three acts.
Act 1: The Rotting City
Vermouth teeters on the edge of collapse: riots in the streets, plague pyres burning, and robed zealots chanting “Salvation lies in the Maw” as they haul the sick toward the Cathedral. An hourly DC 13 Constitution saving throw mechanic tracks plague exposure — three failures mean full disease contraction, and visibly sick characters attract zealot attention. Five key locations define the city. The City Gates present the first challenge: a quarantined city requiring Persuasion, bribery, Deception, or stealth to enter — forced entry rings alarm bells and alerts Vorne’s forces. Plague Square forces an immediate moral choice when zealots move to take a feverish child, with consequences rippling based on whether the party intervenes, bluffs, fights, or does nothing. The Shattered Apothecary hides a Plague Doctor Ghoul among the wreckage alongside a partial cure formula — notes revealing the plague is unnatural, hidden potions of healing, and a concealed cellar with ingredient lists that could save lives if completed. The Streets of Vermouth erupt into full-scale riot just before the Cathedral, offering four approaches: side with the zealots for access at the cost of citizens’ trust, fight alongside rioters for popular support at the cost of heightened Cathedral security, attempt a near-impossible DC 18 diplomatic resolution, or sneak through via rooftop group skill challenge. The Cathedral of Vorne itself can be entered through persuasion, bribery, secret passages, or forced combat — and the moment the party crosses the threshold, the doors boom shut, and a rhythmic heartbeat rises from below.
Act 2: Descent into the Maw
The dungeon spans three levels, each more organic than the last, as stone gives way to flesh, then to active digestion.
Level 1: The False Ruin presents five chambers of psychological dread. The Sealed Hall traps the party immediately — the exit disappears behind them — introducing Malakar’s observation that this is his test of the party’s worth. The Disappearing Door puzzle forces players to physically watch all three exits simultaneously or lose them to blank walls, with only the cleanest threshold (DC 15 Investigation) marking the true path. Gelatinous Shadows — remnants of previously absorbed adventurers infused into the Maw’s ooze — attack from the walls. The Hall of Whispers delivers the Maw’s voice directly into characters’ minds with no physical enemy to fight; DC 14 Wisdom saves determine whether the psychic assault costs a die roll or merely draws mocking laughter. The Rune Hall reveals bioluminescent neural pathways etched across living walls and grants the Arcane Rune Stone — a focus for the dungeon’s consciousness — to those who dare claim it.
Level 2: The Flesh Tunnels drops all pretense of stone as five rooms push endurance and creativity. The Veins of the Maw contract like a swallowing throat, forcing DC 14 Dexterity saves as pseudopods lash from living walls. The Acid Maw Chamber floods the floor with 2d6 acid per round, demanding Acrobatics checks, improvised traversal, or spellwork to cross. The Living Vault embeds treasures of past victims into the flesh — taking them all triggers two Mawborn Guardians, while restraint rewards careful characters. The Pulsing Bridge of hardened tendons rhythmically contracts across a chasm of organ cavity, requiring timing to cross safely or risk falling into acid below. At the Salve’s Rest, Malakar himself appears — half-translucent, partially fused with the dungeon — and presents the Alchemical Salve (acid resistance for 8 hours, essential for Level 3) as a bargaining chip before withdrawing to the Heart, promising a proper meeting ahead.
Level 3: The Digestive Chamber is openly hostile, with hourly DC 13 Constitution saves against exhaustion from toxic fumes and standing acid pools dealing 1d10 damage per round. The Hunger Maw corridor is a living esophagus that seals behind the party and spawns Gelatinous Cysts from burst wall sections while constricting walls grapple and acid-damage those who fall behind. The Flesh Spiral staircase constricts like a giant constrictor snake, dealing 3d6 bludgeoning damage and restraining those who fail round-by-round DC 15 Athletics or Acrobatics checks. The Chamber of Eyes covers every wall with hundreds of watching eyes that launch DC 16 Wisdom saves against psychic damage and personal fear manifestations, resisted more by mutual reassurance and creative covering than combat. Malakar’s Prison stages the warlock’s full reveal — physically merged with the dungeon, speaking with doubled voice — offering temptation or intel before his final retreat. The Core Antechamber confronts the party with the Maw-born Abomination, a grotesque amalgam of absorbed remains guarding the entrance to the Heart, with the Eldritch Lens rewarding those who finish the fight.
Act 3: The Heart of the Maw
The Heart chamber is a cathedral of living flesh — bone ribs overhead, acid weeping from the floor, bioluminescent gloom, and psychic static forcing DC 15 Wisdom saves against the Frightened condition. High Priest Vorne awaits with arms outstretched — only to be seized by a tendril and consumed instantly before the party can intervene, demonstrating that even the Maw’s most devoted servant is expendable. Malakar then reveals himself as the true antagonist, calling on the Maw’s full power for the final battle.
The encounter pits the party against Malakar (Ascendant Warlock) with four lair actions — Acidic Flood (4d6 acid in a 20-foot radius), Hungry Tendrils (grapple and restrain against walls), Psychic Onslaught (3d6 psychic damage plus stun), and Shifting Flesh (prone and forced movement) — while the Maw’s Heart hangs invulnerable overhead until Malakar falls. At half health, Malakar merges further into the Maw for a Phase 2 transformation with new attacks. Before combat, a sufficiently impressive party may receive Malakar’s temptation offer — accept the Maw’s gift, refuse outright, or attempt a DC 17 Deception bluff for first-round surprise. An alternative Ritual Path lets players with the Eldritch Lens attempt to bind the Maw through a 3-success-before-3-failure skill challenge using Arcana, Constitution concentration, and Charisma — but Malakar targets ritual leaders and lair actions intensify against casters.
Three endings determine Vermouth’s fate: Destroy the Maw collapses the Cathedral into a sinkhole, lifts the plague, and scars the city — though a retreating sliver of ooze may hint the horror is never truly finished; Bind the Maw leaves the party as dark guardians of a pacified ancient hunger, raising ethical dilemmas about what to feed it and granting a potential Dark Blessing of acid resistance and ooze telepathy; Fail unleashes the Maw fully, consuming Vermouth within days and launching a larger campaign to stop it before it spreads.
Release Date: 2025
Format: Digital (PDF)
Items Included
- The Maw of the Cube 5E (PDF)
- A B&W Printer-Friendly Version (PDF)
- Maps
- Illustrations (Generated with Midjourney)
- Monster Stat Blocks
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