The Isle of Stonegaze
A Level 10 one-shot. The party sails to the Isle of Stonegaze aboard the trireme Ariadne's Thread, surviving a midvoyage harpy attack before beaching on a silent island ruled by a living gorgon. They must cross a cursed saltmarsh, decipher a scroll written by a man who knows too much, and descend into Euryale's cave — where a still reflecting pool holds the only weapon that can kill the Stone Queen without looking her in the eye.
📜 Session Summary
| Win Condition Defeat or permanently petrify Euryale in her cave lair and recover the Eye of Medusa |
| Setting Open Aegean sea → trireme deck under harpy assault → salt-crusted marshland and ruined temple courtyard → deep cave shrine of a living gorgon |
| Atmosphere Salt air and divine dread; sun-bleached ruin under a stillness that should not exist on a living island — stone stares back from every corner |
| Materials Brine-soaked pine planking, salt-crusted limestone, petrified flesh-stone, copper brazier-light tinted green, sacred still water, sea-faded papyrus |
| Tone Mythic horror threaded with a puzzle — the gorgon's gaze is not the greatest danger; her patience is; every tool the party needs already exists on the island if they listen to the people hiding there |
| Players 6 × Level 10 |
| Est. Duration ~3.5 hours |
| Encounters 3 (Encounters 1 & 2 have non-combat resolution paths; Encounter 3 is a Deadly boss fight with a puzzle-win track) |
| Key Maguffin The Scroll of Theron (handout) · Polished Bronze Mirror (tool) · Blindfold of Apollo (protection) |
Description
Theron of Corinth is a careful man who tells the truth in perfect, incomplete sentences. He needs adventurers to sail to an uninhabited island, enter a cave, and retrieve a gem called the Eye of Medusa. The pay is generous. The danger, he says, is "manageable." He gives one of them a scroll at the tavern, rolled tight and sealed with wax, and asks them to keep it until they need it.
The island is not uninhabited. The survivors hiding near the shore — a scarred fisherwoman and a blind old priest — can teach the party more in ten minutes than Theron did in an hour. The marsh between the beach and the ruins is held by lizardfolk driven mad by a spreading curse. Beyond the marsh, a temple stands empty except for a few items left by those who tried this before. In the cave below the temple, among dozens of petrified adventurers frozen mid-step, a pool of still water glows faintly in the dark.
The Stone Queen knows the pool is there. She has known it since long before Theron's scroll was written. She has spent centuries learning to avoid it — and she will use every legendary action available to stay away from it. The party's job is to change her mind.
The scroll reads: "Where serpents crown the stone queen, let her own gaze be her ruin — the still pool sees what mortal eyes dare not." Distribute it to one player at the tavern briefing. Do not explain it. Track when players engage with it:
Act 1 (Enc 1, ship): No direct payoff — but the scroll exists and players may read it mid-combat. Old Lysander will react if shown it on shore (DC 13 Insight). Kleon cannot explain it but notes "old island lore always involves mirrors."
Act 2 (Enc 2, marsh / ruins): Pyrrha (DC 14 Persuasion) mentions "a pool that glows like moonlight in the cave — they say it shows you things." Old Lysander, if shown the scroll, pauses and says: "The pool is the secret. She will not look at it willingly. But you can make her look." If asked how he knows — "Because I looked into it myself. And it showed me her." Maren (if recruited) confirms fire alone won't kill Euryale — something must break her will first.
Act 3 (Enc 3, cave): The pool is described prominently when the party enters. Euryale's first action is to use Legendary Move away from it. If no player has connected the dots, give a final prompt — a petrified figure frozen mid-point toward the pool.
The Scroll of Theron
Key NPCs
Theron of Corinth
Lean man in his 50s. Ink-stained fingers, watchful grey eyes, merchant's clothes worn by a scholar's mind. Hires the party to retrieve the Eye of Medusa for "academic study." Deflects direct questions with questions. Grows visibly tense if asked about past expeditions to the island.
Secret: His daughter Callista was petrified on the island during an expedition he funded years ago. He believes the Eye can restore her. He is not forthcoming about the danger he is sending the party into — and he has not told them he failed once before.
DC 14 Insight: He knows more than he's saying about the island's dangers. DC 16 Persuasion / DC 13 Intimidation: He admits a "personal connection" but not the full truth. DC 18 Investigation (his satchel/notes): A sketch of a young woman and the name Callista.
Kleon, Captain of the Ariadne's Thread
Barrel-chested with a salt-and-pepper beard and a scar from an anchor chain. Straight-talking and efficient — does not traffic in fear or drama. If the ship is in danger, he says so plainly and acts. Respects competence above all. Will not set foot on the island.
RP Hook: He has made this run before — for Theron, three years ago. He never went ashore. He does not speak about what he saw when only one person came back. DC 14 Persuasion: He says only: "Whatever you find in that cave — take it and go. Don't look at her."
Combat Role (Enc 1): Helper NPC. On init 5 each round: attacks (spear +4, 1d6+2) or repairs sail (Athletics DC 12, restores 10 HP to one section).
Pyrrha
Mid-30s, dark-haired, lean and weathered. A deep scar on her right arm from a lamia's claws. Moves quietly and keeps her back to walls. Has survived on the island for six months by staying away from the ruins and living off fish and rainwater. Wants off this island desperately and will help the party in exchange for passage.
What She Knows: A safe route through the saltmarsh. Locations of the Polished Bronze Mirror (collapsed altar) and Stonechill Water vials (urn near cave steps) in the ruins. Mentions "a pool that glows like moonlight in the cave." Will not go near the ruins or the cave herself.
DC 12 Persuasion / Promise of rescue: Guides the party to the marsh crossing. DC 14 Persuasion: Reveals item locations and lizardfolk patrol timing (advantage on initiative, Enc 2). DC 16 Persuasion: Reveals that Euryale's cave entrance can be approached from above, via a crack in the cliff — cuts Enc 3 setup time by one round.
Old Lysander, Priest of Apollo
Ancient and skeletal-thin. Milk-white eyes — he lost his sight twenty years ago when he glimpsed Euryale's reflection in the pool during a failed exorcism. Wears an Apollo pendant. Speaks slowly and cryptically. He is not surprised by the party's arrival. He believes Apollo guided them here and that the island's curse will end when the party succeeds.
Secret: He knows Euryale cannot be killed by ordinary violence. He knows the pool is the only path. He has been waiting for someone to come with the scroll he once wrote and sent with Theron.
Handouts: Freely gives the party the Blindfolds of Apollo (3 available) if told they intend to enter the cave. Will confirm the scroll's meaning if shown it (DC 13 Insight to notice he pauses and his fingers tighten on his staff).
DC 13 Insight (showing him the scroll): He says: "The pool is the secret. She will not look at it willingly. But you can make her look." If asked how he knows: "Because I looked into it myself. And it showed me her."
Maren, the Marsh-keeper
Weathered woman in her 40s, marsh-stained robes, staff hung with dried reeds and charms. Eyes sharp despite her hermit's solitude. Grateful but wary — prefers solitude but hates what Euryale's curse has done to the marsh. Will aid the party only if they respect the wetland and her autonomy.
Secret: She has been trying to heal the marsh's corruption from the edges for years. She cannot cure it. She knows the corruption will stop if Euryale is destroyed — but she has never found a way in. She will say this plainly if pressed. She knows the lizardfolk attack on sight because the curse has driven them out of the deep marsh; they are desperate, not evil.
DC 13 Persuasion (recruit): Joins the party for Enc 3. DC 10 Nature/Arcana grants advantage. Mentioning Lysander's guidance or sincerely offering to protect the marsh drops DC to 8. Recruited Maren provides 3× Fire Flask and opens Enc 3 with Flaming Sphere.
Session Rewards
Keepable prizes earned by completing (or excelling at) this session. One character claims each reward unless noted. Full cards are under Reward Cards.
| Reward | Description | Criteria |
|---|---|---|
| Polished Bronze Mirror | Altar mirror that angles a gaze attack back upon its source. | Survive Euryale's isle and keep the scavenged mirror after the gaze is turned. |
Creature / Enemy List
Hostile creatures and enemy NPCs by difficulty. Medium = baseline encounter counts; adjust Easy/Hard using encounter scaling notes.
| Creature / Enemy | Easy | Medium | Hard | Notes |
|---|---|---|---|---|
| Corrupted Merfolk | 3 | 5 | 6 | |
| Euryale, the Stone Queen — BOSS | 1 | 1 | 1 | Boss · HP 168 (Deadly: 195, 4 LA) |
| Harpy | 4 | 4 | 4 | |
| Lamia | 1 | 1 | 2 | Enc 3 (Deadly: 2) |
| Lizardfolk Shaman | 1 | 1 | 1 | |
| Lizardfolk Warrior | 3 | 4 | 5 | |
| Medusa Sentinel | 1 | 1 | 2 |
Major Beats
- Tavern, Corinth: Theron delivers his pitch in a rented private room — careful, precise, and incomplete. He hands one PC a sealed scroll ("keep this until you need it") and pays half the agreed fee up front. DC 14 Insight notices he already knows the cave layout when he shouldn't. The party boards the Ariadne's Thread at dawn. Kleon does not smile during departure.
- Three-day voyage: The Aegean is clear but wrong — too quiet, no birds. On the morning of the third day, the island appears through a low haze that doesn't burn off. Kleon orders no anchor within shouting range of the shore. The attack begins an hour later.
- Encounter 1 — Harpies Over the Ariadne's Thread: A flight of harpies and compelled merfolk converge on the ship simultaneously. The sails are the primary target. Outcome determines Long Rest (2+ sails intact) vs. Short Rest (all sails destroyed). Freed merfolk may be recruited to guard the ship.
- Shore landing: The trireme beaches on a stony cove. Kleon and the freed merfolk (if any) stay with the ship. The island is silent — no insects, no gulls. Within ten minutes of walking, the party finds two figures sheltering behind a collapsed sea-wall: Pyrrha, scarred and practical, and Old Lysander, blind and unsurprised. Both can give directions, item locations, and scroll interpretation. Neither will go further inland.
- Encounter 2 — Mireweed Marsh: The path inland is choked by a salt marsh held by displaced lizardfolk. Maren, the Marsh-keeper shelters on its far edge. Defeating the patrol and recruiting Maren provides Fire Flasks, Enc 3 spellcasting support, and confirmation that fire disrupts lamia concentration. DC 13 Persuasion to recruit; DC 10 Nature/Arcana grants advantage.
- Temple ruins (no combat): Between the marsh and the cave, the party passes through a roofless temple courtyard — floor cracked, altar collapsed. Two useful items can be scavenged here with Pyrrha's guidance: the Polished Bronze Mirror (under the fallen altar, DC 14 Perception) and Stonechill Water vials (urn near the cave steps, DC 12 Perception). Lysander has the Blindfolds of Apollo and gives them freely to anyone entering the cave. The scroll becomes urgent here — the party should understand what the pool means before they descend.
- Encounter 3 — The Cave of Euryale: The cave is lit by green-tinted braziers. Petrified figures — adventurers, pilgrims, sailors — stand frozen throughout, some mid-sentence. The still pool glows at the center. Lamias and a Medusa Sentinel hold the antechamber. Euryale enters at round 3, already aware the party has the scroll. She will spend every Legendary Action she has to stay away from that pool. The party must bring it to her.
- Aftermath: The Eye of Medusa comes free with Euryale's defeat (worn amulet). Return to Theron triggers the epilogue — he reacts to the gem's color before controlling himself. Callista is the moral question waiting in Corinth.
Encounter 1 — "Harpies Over the Ariadne's Thread"
Overview
A flight of Harpy descend on the trireme, targeting the sails and rigging while their luring song disrupts the crew. Simultaneously, Corrupted Merfolk board from both sides — drawn by the harpies' compulsion, not inherently evil; they can be freed and potentially recruited. This encounter is a split-priority fight: protect the sails while managing a boarding action from two directions.
Creatures (APL10 Hard — ~11,500 XP adjusted)
- 4× Harpy (CR 1, 200 XP each)
- 1× Harpy Matriarch (CR 5, 1,800 XP) — enters round 2 from altitude, Luring Song DC 13, HP 60, fly 60 ft., +2 to all attacks/saves
- 6× Corrupted Merfolk (CR ½, 100 XP each — deeper compulsion, +1 AC)
- 2× Reef Stalker Merfolk (CR 3, 700 XP each) — elite merfolk wearing coral-plate, reach 10 ft. tridents
- Wave 2 (round 5): 2 more Corrupted Merfolk board from the stern
Hard threshold (6×L10): 10,800 XP · Adjusted: ~11,500 XP. Long Rest only if 2+ sails survive.
🗺 Terrain & Features
Trireme Deck / Open Sea — 80 ft × 25 ft (deck) + sea surrounds
- 3× Sail sections (AC 11, HP 15 each) — primary objectives; harpies target them over PCs unless PCs are in melee reach
- Port and starboard rails (DC 13 Athletics to climb back if knocked overboard)
- Mast (DC 14 Athletics to climb; half cover once at top; harpies prefer altitude)
- Rope coils, oar-banks, rowing benches — difficult terrain in the center 30 ft. strip
- Open sea (30 ft. drop off rail) — merfolk knocked overboard retreat rather than re-board
Mechanics
- Primary Goal: Protect the sails before they are destroyed
- The ship has 3 mast rope / sail sections, each with AC 11, HP 15. Harpies target sails over party members unless a PC is in melee reach
- If all 3 sail sections are destroyed, the ship cannot sail — party must row to shore and only earns a Short Rest before Encounter 2
- If at least 1 sail section survives, the ship is seaworthy — party earns a Long Rest aboard before landing
- Luring Song: Harpies target crew members first (not PCs unless no other targets). Charmed crew become obstacles on deck, blocking movement. A PC can spend their action to snap a crew member out of it (DC 12 CHA/Persuasion, or DC 12 STR to physically restrain/drag them)
- Freeing a Merfolk (Action): A PC adjacent to a Corrupted Merfolk can attempt DC 15 Arcana, Insight, or Religion to break the harpy's hold. Success: merfolk becomes friendly and fights for the party. Freed merfolk can be recruited (DC 14 Persuasion) to guard the ship during Encounters 2 & 3
- Captain Kleon, Captain of the Ariadne's Thread acts as helper NPC — on initiative count 5, he attacks (spear +4, 1d6+1) or attempts to lash a damaged rope (Athletics DC 12, restores 10 HP to one sail section)
- Overboard: Any creature knocked off the ship must use their full movement to climb back (Athletics DC 13). Merfolk knocked off retreat rather than re-board
| Avg. Level | Enemy Adjustments | Rest Outcome |
|---|---|---|
| Lvl 4 | 2 Harpies, 3 Corrupted Merfolk. Sail HP 10 each. Luring Song DC 9. Harpies don't target sails until round 3. | Long rest if any 2 sails survive. Short rest if all destroyed. |
| Lvl 6 | 3 Harpies, 4 Corrupted Merfolk. Sail HP 12 each. Standard Luring Song DC 11. | Long rest if at least 1 sail survives. |
| Lvl 8 ✦ | Intended balance. 4 Harpies, 5 Corrupted Merfolk. Full mechanics as written. | Long rest if at least 1 sail survives. |
| Lvl 10 | 4 Harpies + 1 Harpy Matriarch (Harpy stats, +2 all attack/saves, HP 60, fly 60 ft., Luring Song DC 13, song range 500 ft.). 6 Corrupted Merfolk. Wave 2: 3 additional merfolk board on round 4. | Long rest only if 2+ sails survive. |
Resolution
Creature Cards
Harpy
Medium Monstrosity, Chaotic Evil
AC 11 | HP 38 (7d8+7) | Speed 20 ft., fly 40 ft.
Passive Perception 10 | Languages Common | CR 1 (200 XP)
Actions
Multiattack. Two Claws attacks.
Claws. +3 to hit, reach 5 ft. Hit: 6 (2d4+1) slashing.
Luring Song. Each humanoid and giant within 300 ft. that can hear the harpy must succeed on a DC 11 Wisdom saving throw or be charmed until the song ends. The harpy must use a bonus action on each subsequent turn to continue singing. Charmed targets are incapacitated and must move toward the harpy by the most direct route. Target may re-save (DC 11 WIS) at end of each of its turns. Song ends if the harpy is incapacitated or if a target moves beyond range.
Multiattack. Two Claws attacks.
Claws. +3 to hit, reach 5 ft. Hit: 6 (2d4+1) slashing.
Luring Song. Each humanoid and giant within 300 ft. that can hear the harpy must succeed on a DC 11 Wisdom saving throw or be charmed until the song ends. The harpy must use a bonus action on each subsequent turn to continue singing. Charmed targets are incapacitated and must move toward the harpy by the most direct route. Target may re-save (DC 11 WIS) at end of each of its turns. Song ends if the harpy is incapacitated or if a target moves beyond range.
Corrupted Merfolk
Medium Humanoid (Merfolk), Neutral (Compelled)
AC 11 | HP 22 (4d8+4) | Speed 10 ft., swim 40 ft.
Skills Perception +2 | Languages Aquan, Common | CR 1/4 (50 XP)
Amphibious. Can breathe air and water.
Actions
Spear. +3 to hit, reach 5 ft. or range 20/60 ft. Hit: 4 (1d6+1) piercing, or 5 (1d8+1) two-handed.
Compelled State
A PC adjacent to a Corrupted Merfolk can spend their action making a DC 15 Arcana, Insight, or Religion check to break the harpy compulsion. On success, the merfolk is freed, becomes friendly, and fights for the party. Up to 3 freed merfolk will agree to guard the ship (DC 14 Persuasion).
Spear. +3 to hit, reach 5 ft. or range 20/60 ft. Hit: 4 (1d6+1) piercing, or 5 (1d8+1) two-handed.
A PC adjacent to a Corrupted Merfolk can spend their action making a DC 15 Arcana, Insight, or Religion check to break the harpy compulsion. On success, the merfolk is freed, becomes friendly, and fights for the party. Up to 3 freed merfolk will agree to guard the ship (DC 14 Persuasion).
Encounter 2 — "Mireweed Marsh"
Overview
After meeting Pyrrha and Old Lysander, Priest of Apollo on the rocky shore, the party must cross a salt-choked marsh that blocks the inland approach to the temple. A Lizardfolk Warrior patrol — driven from their nesting grounds by Euryale's spreading petrification curse — attacks on sight. Maren, the Marsh-keeper, a druid hermit sheltering in the crossfire, can be recruited after the fight for critical fire support in the final encounter.
Creatures (APL10 Hard — ~11,300 XP adjusted)
- 5× Lizardfolk Warrior (CR 2, 450 XP each)
- 1× Lizardfolk Shaman (CR 4, 1,100 XP)
- 1× Lizardfolk Warleader (CR 6 variant, 2,300 XP) — elite warrior in Euryale-blessed chitin armor, resistance to petrification, bonus action Javelin Hurl
- Shaman pre-casts Spike Growth on the log bridge approach before initiative
- 1× Maren, the Marsh-keeper (non-hostile — sheltering at far hut)
Hard threshold (6×L10): 10,800 XP · Adjusted: ~11,300 XP. Warleader has Euryale-blessed armor — fire and radiant damage bypass resistance.
🗺 Terrain & Features
Boggy Marshland / Ruined Hut — 100 ft × 80 ft (marsh + channel)
- 4× shallow bog patches (15×15 ft.) — difficult terrain for non-lizardfolk
- 3× mangrove trees — half cover; DC 12 Athletics to climb
- 1× log bridge over deep channel — DC 12 Acrobatics; Spike Growth can be pre-placed here
- Maren's ruined hut (far bank) — three-quarter cover; she is behind it, shouting
- Deep channel — 10 ft. wide, 8 ft. deep; lizardfolk swim freely (Swamp Stride); PCs pay full movement to exit
Mechanics
- Maren, the Marsh-keeper is not immediately recognized as non-hostile — DC 12 Insight or Perception reveals she is cowering behind her ruined hut, shouting that the lizardfolk attacked her unprovoked. If no check is made, she shouts this herself on round 2
- If a PC moves adjacent to Maren before combat ends, she can use her reaction to cast Fog Cloud centered on the Shaman, breaking concentration — a strong coordination moment
- After combat — Recruit Maren: DC 13 Persuasion (appeal to the threat Euryale poses to the marsh). DC 10 Nature or Arcana to recognize her as a druid grants advantage on Persuasion. Showing Old Lysander, Priest of Apollo's scroll reference to "the marsh woman" (if party mentions it) drops DC to 8. Auto-success if a PC sincerely offers to protect the marsh after the quest
- DC 12 Perception (approaching marsh): Party notices bog patches and the log bridge before the lizardfolk spot them — advantage on initiative if they plan an ambush
- Recruited Maren joins Encounter 3 on initiative 8 with spellcasting support (see creature card)
- Map Features: 4× shallow bog patches (15×15 ft., difficult terrain for non-lizardfolk); 3× mangrove trees (half cover, DC 12 Athletics to climb); 1× log bridge over a deep channel (DC 12 Acrobatics; fall costs 15 ft. movement to exit); Maren's ruined hut (three-quarter cover)
- Swamp Stride: Lizardfolk Warriors and Shaman ignore difficult terrain in shallow water (≤3 ft.) and use bog patches for flanking angles
- Shaman Tactics: Opens with Spike Growth on the log bridge or main approach, then switches to Call Lightning from range. Retreats into water if threatened in melee
- Warrior Tactics: Multiattack with bite and javelin; use Clamping Jaws reaction on opportunity attacks (grapple on hit, DC 13 STR escape)
- Atmosphere: Cloudy, dim light; no darkness penalties but visibility feels oppressive — the marsh is too quiet for a wetland full of life
- Harder: Shaman pre-casts Spike Growth before initiative. Warriors use the bridge as a choke point. Add 1 Warrior
- Easier: One Warrior retreats into deep water below half HP. Shaman has 2nd-level spells only (no Call Lightning)
| Clay flasks of rendered fat mixed with marsh-pitch and a striker-wick. Shatters on impact in sticky flame. |
| Action: Throw up to 20 ft. (+PB Dex to hit). On hit: 2d6 fire damage. |
| Bonus Action: Throw up to 10 ft. On hit: 2d6 fire; on miss: 1d6 fire splash anyway. |
| Provided by: Maren, the Marsh-keeper on successful recruitment. |
| Maren knows Euryale's serpent-crowned guardians are vulnerable to sustained flame — radiant and fire damage prevent undead reformation in the ruins ahead, and fire breaks lamia concentration reliably. |
| Encounter 3 benefit: Maren opens with Flaming Sphere (2d6 fire/turn) and can cast Heat Metal on armored foes. Her fire coverage gives the party a reliable tool against Euryale's minions. |
| Provided by: Maren, the Marsh-keeper when recruited; she volunteers this if the party mentions the temple or the cave. |
| Avg. Level | Adjustments |
|---|---|
| Lvl 4 | 3 Lizardfolk Warriors, 1 Shaman (HP 38, 2nd-level spells only). No pre-cast Spike Growth. Maren helps in combat if approached (Fog Cloud only). |
| Lvl 6 | 4 Warriors, 1 Shaman (standard spells). Maren does not act until recruited post-combat. |
| Lvl 8 ✦ | Intended balance. 4 Warriors, 1 Shaman. Full mechanics as written. Maren recruitment grants Fire Flasks and Enc. 3 spell support. |
| Lvl 10 | 5 Warriors, 1 Shaman (4th-level slot: wall of fire). Shaman pre-casts Spike Growth before initiative. Warriors hold the bridge as a kill zone. |
Resolution
Creature Cards
Lizardfolk Warrior
Medium Humanoid (Lizardfolk), Neutral
AC 16 | HP 45 | Speed 30 ft., swim 30 ft.
Skills Perception +3, Stealth +4, Survival +5 | CR 2 (450 XP)
Traits
Hold Breath. 15 minutes.
Swamp Stride. Shallow water (≤3 ft.) does not cost extra movement.
Actions
Multiattack. Bite + Javelin.
Bite. +5, 1d6+3 piercing.
Javelin. +5, 1d6+3 piercing (30/120 ft.).
Clamping Jaws (Reaction). On OA hit, target grappled (DC 13 STR escape).
Hold Breath. 15 minutes.
Swamp Stride. Shallow water (≤3 ft.) does not cost extra movement.
Multiattack. Bite + Javelin.
Bite. +5, 1d6+3 piercing.
Javelin. +5, 1d6+3 piercing (30/120 ft.).
Clamping Jaws (Reaction). On OA hit, target grappled (DC 13 STR escape).
Lizardfolk Shaman
Medium Humanoid (Lizardfolk), Neutral
AC 13 | HP 52 | Speed 30 ft., swim 30 ft.
Skills Nature +4, Perception +6 | CR 4 (1,100 XP)
Spellcasting (WIS, DC 14, +6)
Cantrips: poison spray, produce flame
1st: fog cloud†, healing word, thunderwave
2nd: spike growth†, hold person†
3rd: call lightning†, conjure animals†
Actions
Bite. +4, 1d6+2 piercing.
Cantrips: poison spray, produce flame
1st: fog cloud†, healing word, thunderwave
2nd: spike growth†, hold person†
3rd: call lightning†, conjure animals†
Bite. +4, 1d6+2 piercing.
Maren, the Marsh-keeper
NPC · Druid Hermit · Neutral Good
Appearance: Weathered woman in her 40s, marsh-stained robes, staff hung with dried reeds and charms. Eyes sharp despite her hermit's solitude.
Personality: Grateful but wary. Prefers solitude but hates what Euryale's curse has done to the marsh. Will aid the party if they respect the wetland.
What She Provides: 3× Fire Flask on recruitment. Spellcasting ally in Encounter 3 (init 8). Knows fire is effective against the Stone Queen's guardians.
DC 13 Persuasion: Joins the party.
DC 10 Nature/Arcana: Recognizing her as a druid grants advantage on Persuasion.
Mention marsh woman / Lysander's guidance: DC drops to 8.
Encounter 3 — "The Cave of Euryale" (Boss)
Overview
The party descends into a cave lair lit by green-tinged braziers. Dozens of petrified humanoids stand frozen throughout — adventurers, sailors, pilgrims who came before. A still reflecting pool glows faintly at the center of the cave floor (the scroll's payoff). Two Lamia and a Medusa Sentinel guard the antechamber. After round 3, Euryale, the Stone Queen — BOSS emerges from the inner chamber. Her first Legendary Action will be Move — away from the pool. The fight is about closing that distance.
Creatures (APL10 Deadly — ~19,350 XP adjusted)
- 2× Lamia (CR 4, 1,100 XP each)
- 1× Medusa Sentinel (CR 6, 2,300 XP)
- 1× Euryale, the Stone Queen — BOSS (CR 12, 8,400 XP; APL10: HP 220, 4 Legendary Actions, enters round 2)
- 0–1× Maren, the Marsh-keeper (ally, if recruited in Enc 2)
Deadly threshold (6×L10): 16,800 XP · Adjusted: ~19,350 XP. Pool mechanic (scroll payoff) functions as an effective difficulty reducer — Euryale with 2 consecutive pool-gaze fails is petrified regardless of HP. Budget for 25% more resource drain than raw XP suggests due to Petrifying Gaze pressure and lair actions.
🗺 Terrain & Features
Underground Cave Shrine — 90 ft × 70 ft (irregular) + 30 ft inner chamber
- Still Pool — 15×10 ft. glowing at center; creatures using it for indirect viewing make gaze saves with advantage; Euryale within 30 ft. and in line of sight must save vs. her own gaze
- 8–10 petrified statues — half cover (AC 13, HP 20); shattering releases rubble (DC 12 DEX or 2d6 bludgeoning, 5 ft. radius)
- Green-tinted braziers at four corners — bright light in a 20 ft. radius; extinguishing one (Athletics DC 12, Action) creates dim light zones that impose disadvantage on ranged attacks but interrupt Mirror Vulnerability
- Narrow inner-chamber passage (10 ft. wide, 20 ft. long) — Euryale starts here; choke point favors her Legendary Gaze if party clusters
- Pool edge — creatures adjacent to pool can angle the Polished Bronze Mirror as a Bonus Action (DC 14 Sleight of Hand) to trigger Euryale's Mirror Vulnerability
Mechanics
- The Still Pool (Environmental — Scroll Payoff):
- ◇ Occupies a 15 ft. × 10 ft. area in the center of the cave, glowing faintly with aquatic light
- ◇ Creatures can use it to observe others via reflection — saving throws against Petrifying Gaze made this way have advantage
- ◇ Core mechanic: If Euryale (or any medusa) is within 30 ft. of the pool AND in line of sight of it, she must make a DC 17 CON save against her own Petrifying Gaze at the start of her turn. Fail: restrained. Second consecutive fail: fully petrified. Euryale is immune to the petrified condition normally — the pool overrides this via her own curse
- ◇ Maneuvering Euryale: She is aware of the danger and avoids the pool using Legendary Move. Forcing her toward it requires DC 15 Deception/Persuasion, or using the Polished Bronze Mirror to angle her gaze (DC 14 Sleight of Hand as bonus action)
- Petrified Statues:
- ◇ 8–10 statues throughout the cave provide half cover (AC 13, HP 20 each)
- ◇ If shattered (0 HP), rubble creates 5 ft. radius difficult terrain; creatures in the area make DC 12 DEX save or take 2d6 bludgeoning damage
- ◇ Lamias may deliberately shatter statues near the party
- Euryale's Entrance (Round 3): On initiative count 20 of round 3, she enters from the far end. She spends her first turn observing (only uses Serpent Strike — no Petrifying Gaze yet). This gives scroll-holders one round to react and prepare. She then activates full Petrifying Gaze from round 4 onward
- Lamia Tactics: Prioritize Intoxicating Touch on concentrating spellcasters. Use Suggestion (DC 13 WIS) to force PCs to move away from the pool or drop weapons. Avoid the pool themselves
- Medusa Sentinel Tactics: Stays at range, uses Petrifying Gaze passively (aura), only engages melee if cornered
- Maren (if recruited): Acts on initiative 8. Opens with Flaming Sphere (2d6 fire/turn) on lamias or Euryale; uses Heat Metal on armored foes; Cure Wounds on downed PCs. Her fire damage also disrupts lamia concentration
- Lair Actions (Initiative 20, active from round 3):
- ◇ Serpent Surge: Creatures within 5 ft. of a wall make DC 14 DEX save or take 2d6 piercing from animated stone carvings
- ◇ Stone Dust Cloud: 20 ft. radius centered on Euryale — lightly obscured until start of her next turn
- ◇ Cave Tremor: One 10 ft. × 10 ft. area becomes difficult terrain for the rest of the encounter
- The Eye of Medusa: Dark gem in a golden amulet setting. Glows faintly purple. Powers unclear until Theron evaluates it — possible epilogue hook about his true intentions
| Avg. Level | Enemy Adjustments | Boss Stats & Entry |
|---|---|---|
| Lvl 4 | 2 Lamias only (no Medusa Sentinel). Pool mechanic heavily telegraphed — Lysander explains it directly if shown the scroll. No lair actions. | HP 100, no legendary actions. Gaze DC 13. Enters round 4. |
| Lvl 6 | 2 Lamias, 1 Medusa Sentinel. Lysander hints at the pool. 1 lair action per round (DM's choice). | HP 140, 1 legendary action/round. Gaze DC 15. Enters round 3. |
| Lvl 8 ✦ | Intended balance. 1 Lamia + 1 Medusa Sentinel. Pool mechanic hinted by scroll only. Full lair actions from round 3. | Full stat block. Enters round 3. |
| Lvl 10 | 3 Lamias + 2 Medusa Sentinels. Pool surface is murky until a PC spends an action to clear it (Athletics or Investigation DC 14). Shattered petrified statues release toxic dust (5 ft. radius, DC 13 CON or poisoned). | HP 220, +1 legendary action (4 total). Add: Stone Wrath (3 actions) — 20 ft. cone, DC 17 DEX save, 4d8 bludgeoning on fail. Enters round 2. |
Resolution
- The Eye of Medusa: Dark gem in a golden amulet setting. Glows faintly purple. Powers unclear until Theron evaluates it — possible epilogue hook about his true intentions.
Creature Cards
Lamia
Large Monstrosity, Chaotic Evil
AC 13 (natural armor) | HP 97 (13d10+26) | Speed 30 ft.
Skills Deception +7, Insight +4, Stealth +3 | Senses Darkvision 60 ft. | CR 4 (1,100 XP)
Innate Spellcasting (CHA, DC 13, +5 to hit)
At will: disguise self (humanoid), major image
3/day each: charm person, mirror image, suggestion
1/day: geas
Actions
Multiattack. One Claws + one Dagger. May replace either with Intoxicating Touch.
Claws. +5 to hit, reach 5 ft. Hit: 14 (2d10+3) slashing.
Dagger. +5 to hit, reach 5 ft. or range 20/60 ft. Hit: 5 (1d4+3) piercing.
Intoxicating Touch. Melee spell attack, +5 to hit, reach 5 ft. Target is magically cursed for 1 hour: disadvantage on WIS saves and checks; cannot maintain or regain concentration on spells.
At will: disguise self (humanoid), major image
3/day each: charm person, mirror image, suggestion
1/day: geas
Multiattack. One Claws + one Dagger. May replace either with Intoxicating Touch.
Claws. +5 to hit, reach 5 ft. Hit: 14 (2d10+3) slashing.
Dagger. +5 to hit, reach 5 ft. or range 20/60 ft. Hit: 5 (1d4+3) piercing.
Intoxicating Touch. Melee spell attack, +5 to hit, reach 5 ft. Target is magically cursed for 1 hour: disadvantage on WIS saves and checks; cannot maintain or regain concentration on spells.
Medusa Sentinel
Medium Monstrosity, Lawful Evil
AC 15 (natural armor) | HP 127 (17d8+51) | Speed 30 ft.
Skills Deception +5, Insight +4, Perception +4, Stealth +5
Senses Darkvision 60 ft. | CR 6 (2,300 XP)
Traits
Petrifying Gaze. When a creature that can see the medusa's eyes starts its turn within 30 ft., it must make a DC 14 CON saving throw (if the medusa is not incapacitated and can see it). Fail: restrained (petrification begins). Repeat at end of next turn — fail: petrified; success: effect ends. Avert eyes: no save required; attacks against medusa have disadvantage until your next turn. Petrification lasts until removed by greater restoration.
Actions
Multiattack. One Snake Hair and two Shortsword attacks.
Snake Hair. +5 to hit, reach 5 ft. Hit: 4 (1d4+2) piercing + 14 (4d6) poison. DC 14 CON save or poisoned 1 hour.
Shortsword. +5 to hit, reach 5 ft. Hit: 5 (1d6+2) piercing.
Petrifying Gaze. When a creature that can see the medusa's eyes starts its turn within 30 ft., it must make a DC 14 CON saving throw (if the medusa is not incapacitated and can see it). Fail: restrained (petrification begins). Repeat at end of next turn — fail: petrified; success: effect ends. Avert eyes: no save required; attacks against medusa have disadvantage until your next turn. Petrification lasts until removed by greater restoration.
Multiattack. One Snake Hair and two Shortsword attacks.
Snake Hair. +5 to hit, reach 5 ft. Hit: 4 (1d4+2) piercing + 14 (4d6) poison. DC 14 CON save or poisoned 1 hour.
Shortsword. +5 to hit, reach 5 ft. Hit: 5 (1d6+2) piercing.
Euryale, the Stone Queen — BOSS
Large Monstrosity (Gorgon), Lawful Evil — CR 12 (8,400 XP)
AC 17 (natural armor) | HP 168 (26d10+26) | Speed 30 ft.
Saves DEX +7, CON +6, WIS +6, CHA +9
Skills Deception +9, Insight +6, Perception +6, Stealth +7
Resistances Poison | Condition Immunities Petrified (except via own reflection)
Senses Darkvision 120 ft., Truesight 30 ft.
Traits
Petrifying Gaze (Aura). At the start of each of Euryale's turns, each non-petrified creature within 30 ft. that can see her eyes must make a DC 17 CON saving throw. Fail by 5+: instantly petrified. Fail: restrained (petrification begins; repeat at end of next turn — fail = petrified, success = ends). Avert eyes: no save required, but attacks against Euryale have disadvantage until your next turn.
Mirror Vulnerability. If Euryale can see her own reflection in a polished surface within 30 ft. (requires bright light), she must make a DC 17 CON save against her own Petrifying Gaze. This overrides her condition immunity — it is the nature of the gorgon's ancient curse.
Pool Vulnerability. The Still Pool in the cave acts as a large mirrored surface. If Euryale is within 30 ft. of the pool and in line of sight of it, Mirror Vulnerability triggers automatically at the start of her turn.
Actions
Multiattack. Three attacks: one Snake Hair + two Longsword, or Focused Gaze + two Longsword.
Snake Hair. +7 to hit, reach 10 ft. Hit: 16 (3d8+3) poison. DC 16 CON save or poisoned 1 hour.
Longsword. +5 to hit, reach 5 ft. Hit: 10 (2d8+1) slashing, or 11 (2d10+1) two-handed.
Focused Gaze (replaces one attack). One creature within 30 ft. makes the DC 17 CON save with disadvantage. Standard petrification rules apply.
Legendary Actions — 3/round (end of another creature's turn)
Move. Moves up to half speed without provoking opportunity attacks.
Serpent Strike (1 action). One Snake Hair attack.
Unleash Gaze (2 actions). One creature within 30 ft. that can see Euryale immediately makes the DC 17 CON save against her Petrifying Gaze.
Lair Actions (Initiative 20 — active from round 3)
Serpent Surge. Creatures within 5 ft. of a wall make DC 14 DEX save or take 2d6 piercing from writhing stone carvings.
Stone Dust Cloud. 20 ft. radius centered on Euryale — lightly obscured until start of her next turn.
Cave Tremor. One 10×10 ft. area becomes difficult terrain for the rest of the encounter.
Petrifying Gaze (Aura). At the start of each of Euryale's turns, each non-petrified creature within 30 ft. that can see her eyes must make a DC 17 CON saving throw. Fail by 5+: instantly petrified. Fail: restrained (petrification begins; repeat at end of next turn — fail = petrified, success = ends). Avert eyes: no save required, but attacks against Euryale have disadvantage until your next turn.
Mirror Vulnerability. If Euryale can see her own reflection in a polished surface within 30 ft. (requires bright light), she must make a DC 17 CON save against her own Petrifying Gaze. This overrides her condition immunity — it is the nature of the gorgon's ancient curse.
Pool Vulnerability. The Still Pool in the cave acts as a large mirrored surface. If Euryale is within 30 ft. of the pool and in line of sight of it, Mirror Vulnerability triggers automatically at the start of her turn.
Multiattack. Three attacks: one Snake Hair + two Longsword, or Focused Gaze + two Longsword.
Snake Hair. +7 to hit, reach 10 ft. Hit: 16 (3d8+3) poison. DC 16 CON save or poisoned 1 hour.
Longsword. +5 to hit, reach 5 ft. Hit: 10 (2d8+1) slashing, or 11 (2d10+1) two-handed.
Focused Gaze (replaces one attack). One creature within 30 ft. makes the DC 17 CON save with disadvantage. Standard petrification rules apply.
Move. Moves up to half speed without provoking opportunity attacks.
Serpent Strike (1 action). One Snake Hair attack.
Unleash Gaze (2 actions). One creature within 30 ft. that can see Euryale immediately makes the DC 17 CON save against her Petrifying Gaze.
Serpent Surge. Creatures within 5 ft. of a wall make DC 14 DEX save or take 2d6 piercing from writhing stone carvings.
Stone Dust Cloud. 20 ft. radius centered on Euryale — lightly obscured until start of her next turn.
Cave Tremor. One 10×10 ft. area becomes difficult terrain for the rest of the encounter.
Maren, the Marsh-keeper
NPC · Druid Hermit · Neutral Good
Appearance: Weathered woman in her 40s, marsh-stained robes, staff hung with dried reeds and charms. Eyes sharp despite her hermit's solitude.
Personality: Grateful but wary. Prefers solitude but hates what Euryale's curse has done to the marsh. Will aid the party if they respect the wetland.
What She Provides: 3× Fire Flask on recruitment. Spellcasting ally in Encounter 3 (init 8). Knows fire is effective against the Stone Queen's guardians.
DC 13 Persuasion: Joins the party.
DC 10 Nature/Arcana: Recognizing her as a druid grants advantage on Persuasion.
Mention marsh woman / Lysander's guidance: DC drops to 8.
⚖️ Difficulty Scaling
As Written ★ — 6 Players, Average Level 10
- Baseline for this guide. Encounters 1–2 are Hard (~11,500 and ~11,300 XP adjusted respectively); Encounter 3 is Deadly (~19,350 XP adjusted) for six PCs at average level 10.
- XP thresholds (6×L10): Hard ≈ 10,800 · Deadly ≈ 16,800. The pool mechanic in Enc 3 functions as an effective difficulty modifier — Euryale petrified by her own reflection bypasses HP entirely. Budget for 25% more resource drain in Enc 3 due to Petrifying Gaze and lair action pressure.
- Skill DCs: Enc 1 (free merfolk DC 15; recruit DC 14); Enc 2 (Maren recruit DC 13, Perception DC 12–14); Enc 3 (pool maneuver DCs 14–15; Deception/Persuasion to bait Euryale DC 15).
- Long Rest gate: party earns a Long Rest aboard ship if 2+ sails survive Enc 1; Short Rest only otherwise. This is the primary resource lever between Enc 1 and Enc 3.
Library Standard — 6 Players, Average Level 8
- Enc 1: Remove Harpy Matriarch; 4 Harpies + 5 standard Corrupted Merfolk (no Wave 2). Long Rest if any sail survives. Sail HP 12 each.
- Enc 2: 4 Warriors + 1 Shaman (no Warleader). Shaman does not pre-cast Spike Growth. Maren recruit DC 12.
- Enc 3: 1 Lamia + 1 Medusa Sentinel. Euryale HP 168, 3 Legendary Actions, enters round 3. Pool surface is clear from the start. All DCs −1.
Easier (APL 8–9)
- Apply Library Standard adjustments. Additionally: Lysander explains the pool mechanic directly if shown the scroll (no Insight check required). Lamia does not use Suggestion to move PCs away from the pool. Lair actions begin round 4 instead of round 3. Euryale does not use Focused Gaze in her first turn.
Harder (APL 11–12)
- Enc 1: Add 1 Harpy Matriarch; Wave 2 triggers on round 3 instead of round 5; Reef Stalkers have Trident Throw (30/90 ft., 2d6+3 piercing). Sail HP 12 each (more fragile).
- Enc 2: Warleader has Legendary Resistance 1/day. Add 1 Lizardfolk Shaman Acolyte (CR 2) lurking in the deep channel. Spike Growth covers both entry paths. All DCs +1.
- Enc 3: Add 1 more Lamia (3× total). Pool surface is murky until a PC spends an Action to clear it (Athletics or Investigation DC 14). Shattered statues release toxic dust (5 ft. radius, DC 13 CON or poisoned 1 hour). Euryale gains Stone Wrath (3 Legendary Actions): 20 ft. cone, DC 17 DEX save, 4d8 bludgeoning on fail. Lair actions begin round 2.
📋 Appendix — Cards
Full stat blocks for every creature, NPC, and item in this session (including optional / difficulty-adjusted entries).
Creature Cards
Harpy
Medium Monstrosity, Chaotic Evil
AC 11 | HP 38 (7d8+7) | Speed 20 ft., fly 40 ft.
Passive Perception 10 | Languages Common | CR 1 (200 XP)
Actions
Multiattack. Two Claws attacks.
Claws. +3 to hit, reach 5 ft. Hit: 6 (2d4+1) slashing.
Luring Song. Each humanoid and giant within 300 ft. that can hear the harpy must succeed on a DC 11 Wisdom saving throw or be charmed until the song ends. The harpy must use a bonus action on each subsequent turn to continue singing. Charmed targets are incapacitated and must move toward the harpy by the most direct route. Target may re-save (DC 11 WIS) at end of each of its turns. Song ends if the harpy is incapacitated or if a target moves beyond range.
Multiattack. Two Claws attacks.
Claws. +3 to hit, reach 5 ft. Hit: 6 (2d4+1) slashing.
Luring Song. Each humanoid and giant within 300 ft. that can hear the harpy must succeed on a DC 11 Wisdom saving throw or be charmed until the song ends. The harpy must use a bonus action on each subsequent turn to continue singing. Charmed targets are incapacitated and must move toward the harpy by the most direct route. Target may re-save (DC 11 WIS) at end of each of its turns. Song ends if the harpy is incapacitated or if a target moves beyond range.
Corrupted Merfolk
Medium Humanoid (Merfolk), Neutral (Compelled)
AC 11 | HP 22 (4d8+4) | Speed 10 ft., swim 40 ft.
Skills Perception +2 | Languages Aquan, Common | CR 1/4 (50 XP)
Amphibious. Can breathe air and water.
Actions
Spear. +3 to hit, reach 5 ft. or range 20/60 ft. Hit: 4 (1d6+1) piercing, or 5 (1d8+1) two-handed.
Compelled State
A PC adjacent to a Corrupted Merfolk can spend their action making a DC 15 Arcana, Insight, or Religion check to break the harpy compulsion. On success, the merfolk is freed, becomes friendly, and fights for the party. Up to 3 freed merfolk will agree to guard the ship (DC 14 Persuasion).
Spear. +3 to hit, reach 5 ft. or range 20/60 ft. Hit: 4 (1d6+1) piercing, or 5 (1d8+1) two-handed.
A PC adjacent to a Corrupted Merfolk can spend their action making a DC 15 Arcana, Insight, or Religion check to break the harpy compulsion. On success, the merfolk is freed, becomes friendly, and fights for the party. Up to 3 freed merfolk will agree to guard the ship (DC 14 Persuasion).
Lamia
Large Monstrosity, Chaotic Evil
AC 13 (natural armor) | HP 97 (13d10+26) | Speed 30 ft.
Skills Deception +7, Insight +4, Stealth +3 | Senses Darkvision 60 ft. | CR 4 (1,100 XP)
Innate Spellcasting (CHA, DC 13, +5 to hit)
At will: disguise self (humanoid), major image
3/day each: charm person, mirror image, suggestion
1/day: geas
Actions
Multiattack. One Claws + one Dagger. May replace either with Intoxicating Touch.
Claws. +5 to hit, reach 5 ft. Hit: 14 (2d10+3) slashing.
Dagger. +5 to hit, reach 5 ft. or range 20/60 ft. Hit: 5 (1d4+3) piercing.
Intoxicating Touch. Melee spell attack, +5 to hit, reach 5 ft. Target is magically cursed for 1 hour: disadvantage on WIS saves and checks; cannot maintain or regain concentration on spells.
At will: disguise self (humanoid), major image
3/day each: charm person, mirror image, suggestion
1/day: geas
Multiattack. One Claws + one Dagger. May replace either with Intoxicating Touch.
Claws. +5 to hit, reach 5 ft. Hit: 14 (2d10+3) slashing.
Dagger. +5 to hit, reach 5 ft. or range 20/60 ft. Hit: 5 (1d4+3) piercing.
Intoxicating Touch. Melee spell attack, +5 to hit, reach 5 ft. Target is magically cursed for 1 hour: disadvantage on WIS saves and checks; cannot maintain or regain concentration on spells.
Medusa Sentinel
Medium Monstrosity, Lawful Evil
AC 15 (natural armor) | HP 127 (17d8+51) | Speed 30 ft.
Skills Deception +5, Insight +4, Perception +4, Stealth +5
Senses Darkvision 60 ft. | CR 6 (2,300 XP)
Traits
Petrifying Gaze. When a creature that can see the medusa's eyes starts its turn within 30 ft., it must make a DC 14 CON saving throw (if the medusa is not incapacitated and can see it). Fail: restrained (petrification begins). Repeat at end of next turn — fail: petrified; success: effect ends. Avert eyes: no save required; attacks against medusa have disadvantage until your next turn. Petrification lasts until removed by greater restoration.
Actions
Multiattack. One Snake Hair and two Shortsword attacks.
Snake Hair. +5 to hit, reach 5 ft. Hit: 4 (1d4+2) piercing + 14 (4d6) poison. DC 14 CON save or poisoned 1 hour.
Shortsword. +5 to hit, reach 5 ft. Hit: 5 (1d6+2) piercing.
Petrifying Gaze. When a creature that can see the medusa's eyes starts its turn within 30 ft., it must make a DC 14 CON saving throw (if the medusa is not incapacitated and can see it). Fail: restrained (petrification begins). Repeat at end of next turn — fail: petrified; success: effect ends. Avert eyes: no save required; attacks against medusa have disadvantage until your next turn. Petrification lasts until removed by greater restoration.
Multiattack. One Snake Hair and two Shortsword attacks.
Snake Hair. +5 to hit, reach 5 ft. Hit: 4 (1d4+2) piercing + 14 (4d6) poison. DC 14 CON save or poisoned 1 hour.
Shortsword. +5 to hit, reach 5 ft. Hit: 5 (1d6+2) piercing.
Euryale, the Stone Queen — BOSS
Large Monstrosity (Gorgon), Lawful Evil — CR 12 (8,400 XP)
AC 17 (natural armor) | HP 168 (26d10+26) | Speed 30 ft.
Saves DEX +7, CON +6, WIS +6, CHA +9
Skills Deception +9, Insight +6, Perception +6, Stealth +7
Resistances Poison | Condition Immunities Petrified (except via own reflection)
Senses Darkvision 120 ft., Truesight 30 ft.
Traits
Petrifying Gaze (Aura). At the start of each of Euryale's turns, each non-petrified creature within 30 ft. that can see her eyes must make a DC 17 CON saving throw. Fail by 5+: instantly petrified. Fail: restrained (petrification begins; repeat at end of next turn — fail = petrified, success = ends). Avert eyes: no save required, but attacks against Euryale have disadvantage until your next turn.
Mirror Vulnerability. If Euryale can see her own reflection in a polished surface within 30 ft. (requires bright light), she must make a DC 17 CON save against her own Petrifying Gaze. This overrides her condition immunity — it is the nature of the gorgon's ancient curse.
Pool Vulnerability. The Still Pool in the cave acts as a large mirrored surface. If Euryale is within 30 ft. of the pool and in line of sight of it, Mirror Vulnerability triggers automatically at the start of her turn.
Actions
Multiattack. Three attacks: one Snake Hair + two Longsword, or Focused Gaze + two Longsword.
Snake Hair. +7 to hit, reach 10 ft. Hit: 16 (3d8+3) poison. DC 16 CON save or poisoned 1 hour.
Longsword. +5 to hit, reach 5 ft. Hit: 10 (2d8+1) slashing, or 11 (2d10+1) two-handed.
Focused Gaze (replaces one attack). One creature within 30 ft. makes the DC 17 CON save with disadvantage. Standard petrification rules apply.
Legendary Actions — 3/round (end of another creature's turn)
Move. Moves up to half speed without provoking opportunity attacks.
Serpent Strike (1 action). One Snake Hair attack.
Unleash Gaze (2 actions). One creature within 30 ft. that can see Euryale immediately makes the DC 17 CON save against her Petrifying Gaze.
Lair Actions (Initiative 20 — active from round 3)
Serpent Surge. Creatures within 5 ft. of a wall make DC 14 DEX save or take 2d6 piercing from writhing stone carvings.
Stone Dust Cloud. 20 ft. radius centered on Euryale — lightly obscured until start of her next turn.
Cave Tremor. One 10×10 ft. area becomes difficult terrain for the rest of the encounter.
Petrifying Gaze (Aura). At the start of each of Euryale's turns, each non-petrified creature within 30 ft. that can see her eyes must make a DC 17 CON saving throw. Fail by 5+: instantly petrified. Fail: restrained (petrification begins; repeat at end of next turn — fail = petrified, success = ends). Avert eyes: no save required, but attacks against Euryale have disadvantage until your next turn.
Mirror Vulnerability. If Euryale can see her own reflection in a polished surface within 30 ft. (requires bright light), she must make a DC 17 CON save against her own Petrifying Gaze. This overrides her condition immunity — it is the nature of the gorgon's ancient curse.
Pool Vulnerability. The Still Pool in the cave acts as a large mirrored surface. If Euryale is within 30 ft. of the pool and in line of sight of it, Mirror Vulnerability triggers automatically at the start of her turn.
Multiattack. Three attacks: one Snake Hair + two Longsword, or Focused Gaze + two Longsword.
Snake Hair. +7 to hit, reach 10 ft. Hit: 16 (3d8+3) poison. DC 16 CON save or poisoned 1 hour.
Longsword. +5 to hit, reach 5 ft. Hit: 10 (2d8+1) slashing, or 11 (2d10+1) two-handed.
Focused Gaze (replaces one attack). One creature within 30 ft. makes the DC 17 CON save with disadvantage. Standard petrification rules apply.
Move. Moves up to half speed without provoking opportunity attacks.
Serpent Strike (1 action). One Snake Hair attack.
Unleash Gaze (2 actions). One creature within 30 ft. that can see Euryale immediately makes the DC 17 CON save against her Petrifying Gaze.
Serpent Surge. Creatures within 5 ft. of a wall make DC 14 DEX save or take 2d6 piercing from writhing stone carvings.
Stone Dust Cloud. 20 ft. radius centered on Euryale — lightly obscured until start of her next turn.
Cave Tremor. One 10×10 ft. area becomes difficult terrain for the rest of the encounter.
Lizardfolk Warrior
Medium Humanoid (Lizardfolk), Neutral
AC 16 | HP 45 | Speed 30 ft., swim 30 ft.
Skills Perception +3, Stealth +4, Survival +5 | CR 2 (450 XP)
Traits
Hold Breath. 15 minutes.
Swamp Stride. Shallow water (≤3 ft.) does not cost extra movement.
Actions
Multiattack. Bite + Javelin.
Bite. +5, 1d6+3 piercing.
Javelin. +5, 1d6+3 piercing (30/120 ft.).
Clamping Jaws (Reaction). On OA hit, target grappled (DC 13 STR escape).
Hold Breath. 15 minutes.
Swamp Stride. Shallow water (≤3 ft.) does not cost extra movement.
Multiattack. Bite + Javelin.
Bite. +5, 1d6+3 piercing.
Javelin. +5, 1d6+3 piercing (30/120 ft.).
Clamping Jaws (Reaction). On OA hit, target grappled (DC 13 STR escape).
Lizardfolk Shaman
Medium Humanoid (Lizardfolk), Neutral
AC 13 | HP 52 | Speed 30 ft., swim 30 ft.
Skills Nature +4, Perception +6 | CR 4 (1,100 XP)
Spellcasting (WIS, DC 14, +6)
Cantrips: poison spray, produce flame
1st: fog cloud†, healing word, thunderwave
2nd: spike growth†, hold person†
3rd: call lightning†, conjure animals†
Actions
Bite. +4, 1d6+2 piercing.
Cantrips: poison spray, produce flame
1st: fog cloud†, healing word, thunderwave
2nd: spike growth†, hold person†
3rd: call lightning†, conjure animals†
Bite. +4, 1d6+2 piercing.
NPC Cards
Theron of Corinth
NPC · Questgiver · Neutral (suspected)
Appearance: A lean man in his 50s. Sun-creased skin, ink-stained fingers, watchful grey eyes. Dresses like a merchant; carries himself like a scholar who has seen too much.
Motivation (Surface): Claims to want the Eye of Medusa for academic study — it is said to reveal hidden truths and pierce illusions.
True Motivation (DM Only): His daughter Callista was petrified on the island during an expedition he funded years ago. He believes the Eye can restore her. He is not forthcoming about this, or about the true danger he is sending the party into.
Personality: Careful. Precise. Charming in a calculating way. Deflects direct questions with questions. Grows visibly tense if asked about the island's history or past expeditions.
DC 14 Insight: He knows more than he's saying about the island's dangers.
DC 16 Persuasion / DC 13 Intimidation: He admits a "personal connection" but not the full truth.
DC 18 Investigation (his notes / satchel): A sketch of a young woman and a name: Callista.
Kleon, Captain of the Ariadne's Thread
NPC · Trireme Captain · Lawful Neutral
Appearance: Barrel-chested, salt-and-pepper beard, scar across his left forearm from an anchor chain. Permanently squinting from years at sea.
Personality: Straight-talking and efficient. Does not traffic in fear or drama. Respects competence above all. If the ship is in danger, he says so plainly and acts.
Role in Encounter 1: Helper NPC. On initiative count 5 each round, he can make one attack or attempt to repair a sail section (Athletics DC 12 — restores 10 HP to one section).
Combat Stats (if needed): AC 13, HP 45, Speed 30 ft.
STR 15 (+2) | DEX 13 (+1) | CON 14 (+2) | INT 11 | WIS 12 (+1) | CHA 10
Spear: +4 to hit, 1d6+2 piercing.
Pyrrha
NPC · Island Survivor · Neutral Good
Appearance: Mid-30s, dark-haired, lean and weathered. Moves quietly; keeps her back to walls. A deep scar on her right arm from a lamia's claws six months ago.
Personality: Fearful but pragmatic. She has survived on the island by staying out of the ruins and living off fish and rainwater. She wants off this island desperately and will help the party in exchange for passage.
What She Knows: A safe route through the saltmarsh to the temple. Locations of the Polished Bronze Mirror (collapsed altar) and Stonechill Water vials (urn near cave steps) in the ruins beyond the marsh. The cave has "a pool that glows like moonlight."
DC 12 Persuasion / Promise of rescue: Guides the party to the marsh crossing.
DC 14 Persuasion: Reveals item locations in the temple ruins (between Encounters 2 and 3). Describes lizardfolk patrol timing — advantage on initiative for Encounter 2.
Old Lysander, Priest of Apollo
NPC · Island Hermit · Neutral Good
Appearance: Ancient and skeletal-thin, with milk-white eyes. He lost his sight twenty years ago when he glimpsed Euryale's reflection in the pool during a failed exorcism attempt. He wears an Apollo pendant and carries a staff carved with sun-rays.
Personality: Cryptic and slow-speaking. He has meditated for years on the island's curse. He is not surprised by the party's arrival — he expected it. He believes Apollo guided them here.
What He Knows: The Still Pool's power and danger. The layout of the cave (described from memory). The Blindfolds of Apollo, which he carries and offers freely. He will confirm the scroll's meaning if shown it.
DC 13 Insight (upon seeing the scroll): He pauses for a long moment, then says: "The pool is the secret. She will not look at it willingly. But you can make her look."
If asked how he knows: "Because I looked into it myself. And it showed me her."
Maren, the Marsh-keeper
NPC · Druid Hermit · Neutral Good
Appearance: Weathered woman in her 40s, marsh-stained robes, staff hung with dried reeds and charms. Eyes sharp despite her hermit's solitude.
Personality: Grateful but wary. Prefers solitude but hates what Euryale's curse has done to the marsh. Will aid the party if they respect the wetland.
What She Provides: 3× Fire Flask on recruitment. Spellcasting ally in Encounter 3 (init 8). Knows fire is effective against the Stone Queen's guardians.
DC 13 Persuasion: Joins the party.
DC 10 Nature/Arcana: Recognizing her as a druid grants advantage on Persuasion.
Mention marsh woman / Lysander's guidance: DC drops to 8.
Item Cards
Fire Flask
Improvised Weapon · Provided by Maren · 3 Available
Clay flask of rendered fat mixed with marsh-pitch and a striker-wick. Shatters on impact in sticky flame.
Use
Action: Throw 20 ft. (+PB Dex). Hit: 2d6 fire.
Bonus Action: Throw 10 ft. Hit: 2d6 fire; miss: 1d6 fire splash.
Provided by: Maren on recruitment in Encounter 2.
Action: Throw 20 ft. (+PB Dex). Hit: 2d6 fire.
Bonus Action: Throw 10 ft. Hit: 2d6 fire; miss: 1d6 fire splash.
Polished Bronze Mirror
Wondrous Item · Common · Requires one hand
A round bronze shield polished to a perfect reflective shine. The back is embossed with a relief of Athena's owl.
Properties
Indirect Viewing. The wielder can observe creatures and spaces around corners or behind them without exposing themselves to line-of-sight effects (such as gaze attacks).
Gaze Deflection. When the wielder views a creature with a gaze attack via the mirror's reflection rather than direct sight, they make the associated saving throw with advantage.
Reflection (Bonus Action). Angle the mirror toward a medusa within 30 ft. of a large reflective surface (e.g., the Still Pool). Make a DC 14 Sleight of Hand check. On success, the creature must make its own gaze saving throw against itself. Requires positioning within 30 ft. — DM discretion on line of sight.
Found: Under a collapsed altar in the inner temple courtyard (exploration between Encounters 2 and 3). Pyrrha can point the party here (DC 14 Persuasion).
Indirect Viewing. The wielder can observe creatures and spaces around corners or behind them without exposing themselves to line-of-sight effects (such as gaze attacks).
Gaze Deflection. When the wielder views a creature with a gaze attack via the mirror's reflection rather than direct sight, they make the associated saving throw with advantage.
Reflection (Bonus Action). Angle the mirror toward a medusa within 30 ft. of a large reflective surface (e.g., the Still Pool). Make a DC 14 Sleight of Hand check. On success, the creature must make its own gaze saving throw against itself. Requires positioning within 30 ft. — DM discretion on line of sight.
The Still Pool
Environmental Feature · Encounter 3 · Cave of Euryale
A 15 ft. × 10 ft. pool of perfectly still water in the center of the cave floor, glowing faintly with cold aquatic light. It mirrors everything above it with supernatural clarity. Lysander carried water from it out of the cave years ago (see Stonechill Vials).
Properties
Indirect Viewing. A creature using the pool to observe a gaze-attack creature (via reflection) makes the associated save with advantage.
Mirror Surface. Any creature with a gaze attack that is within 30 ft. of the pool and in its line of sight must make its own gaze saving throw against itself at the start of its turn (as per Mirror Vulnerability).
Euryale's Weakness. Euryale knows this danger and actively avoids line of sight to the pool using her Legendary Move action. Forcing her to face it requires maneuvering, deception, or a successful DC 14 Sleight of Hand check with the Polished Bronze Mirror to reflect her gaze toward it.
Indirect Viewing. A creature using the pool to observe a gaze-attack creature (via reflection) makes the associated save with advantage.
Mirror Surface. Any creature with a gaze attack that is within 30 ft. of the pool and in its line of sight must make its own gaze saving throw against itself at the start of its turn (as per Mirror Vulnerability).
Euryale's Weakness. Euryale knows this danger and actively avoids line of sight to the pool using her Legendary Move action. Forcing her to face it requires maneuvering, deception, or a successful DC 14 Sleight of Hand check with the Polished Bronze Mirror to reflect her gaze toward it.
Blindfold of Apollo
Wondrous Item · Common · 3 available
Strips of linen blessed with a prayer to Apollo, god of light and truth. Made by Lysander before he lost his eyes.
Effect
While worn, the wearer is blinded but gains Blindsight 15 ft. and is immune to gaze-based effects (including Petrifying Gaze from any source). Removing the blindfold is a bonus action.
Found: On Old Lysander, who gives them freely if told the party intends to enter the cave.
While worn, the wearer is blinded but gains Blindsight 15 ft. and is immune to gaze-based effects (including Petrifying Gaze from any source). Removing the blindfold is a bonus action.
| Maren knows Euryale's serpent-crowned guardians are vulnerable to sustained flame — radiant and fire damage prevent undead reformation in the ruins ahead, and fire breaks lamia concentration reliably. |
| Encounter 3 benefit: Maren opens with Flaming Sphere (2d6 fire/turn) and can cast Heat Metal on armored foes. Her fire coverage gives the party a reliable tool against Euryale's minions. |
| Provided by: Maren when recruited; she volunteers this if the party mentions the temple or the cave. |
Reward Cards
Post-session keepables. Reward is the first tag. Mechanics below are for ongoing use after this oneshot.
Polished Bronze Mirror
Reward · Wondrous · 1/Short Rest
Mechanics. Once per short rest, as a bonus action, angle the mirror at a creature within 30 feet that uses a gaze attack or that you can see making one. That creature must succeed on a DC 15 Constitution saving throw or be subjected to its own gaze effect (or restrained until the end of its next turn if the gaze has no self-targeting rules). While carried, you have advantage on saving throws against being petrified.
Appearance. A round bronze hand-mirror scavenged from a collapsed altar, face bright as still water.
Lore. Temple bronze that taught a gorgon the oldest cruelty of her curse: her own eyes.
Quote. "Do not look away — look correctly." — Lysander of the isle ruins
Earn when: Survive Euryale's isle and keep the scavenged mirror after the gaze is turned.