For 4–5 players, levels 3–5. Dark fantasy. 2–3 session one-shot or drop-in encounter.
Setup
The village of Greyveil sits at the edge of a vast peat bog in a region where the border between the Material Plane and the Shadowfringe has worn thin. For generations, the villagers have maintained an old compact: every autumn, they leave an offering of iron nails, salt, and a lock of hair at the fen’s edge to keep the thing in the deep water satisfied. This year, the offering was not made. The village elder, Maren Thull, claims she forgot. She didn’t. She’s been having dreams — a child’s voice calling her name from beneath the black water, promising that if she stops the offerings, the “hunger” will finally end and her drowned granddaughter will come home.
Three weeks later, villagers have started disappearing. Not dramatically — they simply walk into the fen at twilight and don’t come back. Their footprints end at the water’s edge. No struggle. No drag marks. The village is down to nineteen souls, and the fog that rolls off the bog now carries the faint sound of children singing.
Hook
The party arrives in Greyveil by whatever means fits the campaign — escorting a merchant caravan, tracking a fugitive, or following rumors of a “ghost village” on old maps. They find a community on the edge of panic. Livestock have been found drained of blood in their pens, the carcasses arranged in spirals. A child’s handprint, grey and cold as stone, was found pressed into the church door. The party is approached by Dren Halwick, a terrified farmer whose wife walked into the fen two nights ago. He’ll pay what little he has — 50 gp and a silver locket — for anyone who’ll go into the bog and bring her back. He doesn’t believe she’s dead. He’s right, but not in the way he hopes.
The Encounter
The fen itself is a haunted swamp environment: difficult terrain, patches of quicksand (DC 13 Strength save or restrained, repeat save each round), and a pervasive fog that limits visibility to 30 feet. The singing grows louder as the party moves deeper. After 30 minutes of travel, they find the first missing villager — standing waist-deep in black water, eyes open, smiling, unresponsive. A DC 14 Wisdom (Medicine) check reveals the person is alive but catatonic, their body temperature dangerously low. There are seven villagers in the water in total, arranged in a loose circle around a raised mound of peat and bone.
On the mound sits the Hollowing — the creature that was once a bheur hag but has since been consumed and repurposed by a Shadowfringe entity it foolishly tried to bind. Use the stat block for a green hag (MM p. 177) with the following modifications:
- AC 15 (natural armor, shadow-chitin)
- HP 91 (14d8 + 28)
- Innate Spellcasting (expanded): Adds phantasmal force (1/day) and shadow of moil (1/day, flavored as tendrils of bog-dark)
- Hollowing Gaze (Recharge 5–6): 30-foot cone, DC 14 Wisdom save or frightened for 1 minute. Frightened targets are compelled to walk toward the water on their next turn.
- Children of the Fen: The seven catatonic villagers can be animated as shadow stat blocks (MM p. 269) if the hag is threatened, rising from the water to defend her. They deal no damage to each other.
The Hollowing speaks with the voice of Maren’s granddaughter, Lissa (age 7 when she drowned). It uses this voice to plead, to cry, to beg the party to “let the old woman stop hurting us.” It claims Maren’s broken compact freed it, and it only wants to “bring the children home.” This is a lie — it’s feeding on the life force of the absorbed villagers and growing stronger. Each day it remains active, it consumes one villager entirely (no resurrection possible without wish).
Twist
Maren Thull has followed the party into the fen. She arrives mid-combat or just after, and she is not what she seems. The real Maren died three weeks ago — the night she stopped the offering. What walks now is a doppelgänger animated by the Hollowing, used to keep the village compliant and prevent outside help from arriving. A DC 16 Wisdom (Insight) check or detect magic reveals the illusion. If confronted, the doppelganger drops its disguise and attacks using the doppelganger stat block (MM p. 82), attempting to drag a PC into the water to feed the Hollowing.
If the party befriended Maren before entering the fen, this revelation should land like a hammer.
Resolution
Destroying the Hollowing breaks its hold on the villagers, who collapse and must be carried out of the bog (they’ll recover fully with rest). The Shadowfringe entity, denied its anchor, lashes out one final time: the fen itself seems to breathe, and every mirror, pool, and reflective surface within a mile shows a brief flash of a vast, pale face before going dark. This is a narrative hook — the entity is not destroyed, only inconvenienced.
If the party investigates the mound, they find the hag’s original coven stone — a cracked obsidian disk inscribed with bindings in Abyssal. A DC 15 Intelligence (Arcana) check reveals it was used to summon and control a Shadowfringe entity. Someone gave this stone to the hag. Who? And why? This can seed an entire campaign arc.
Loot
- The Locket of Greyveil (Dren’s payment): A silver locket containing a painted miniature of his wife. Functions as a periapt of wound closure but only while the wearer is in a swamp or marsh environment.
- Hag’s Tooth Necklace: 3 teeth on a cord. Once per long rest, the wearer can cast speak with dead without material components. The corpse always answers in Abyssal, regardless of what language it spoke in life.
- Coven Stone (cracked): Worth 250 gp to a collector of occult items. Also functions as an arcane focus that adds +1 to spell attack rolls for necromancy spells — but the caster hears whispering after each use. Prolonged use (more than 30 days) requires a DC 12 Wisdom save or gain one level of Shadowfringe Taint (homebrew: disadvantage on saves against fear, eyes occasionally go fully black, animals react with hostility).
- 50 gp from Dren Halwick, as promised.
This encounter is designed to be system-light on the horror and heavy on the moral ambiguity. The Hollowing isn’t evil for evil’s sake — it’s a parasite that learned to mimic love. The real monster is the chain of bad bargains that led here: the village’s compact, the hag’s ambition, Maren’s grief. Let your players feel that weight.
For lower-level parties (1–3), remove the shadow minions and reduce the Hollowing’s HP to 68. For higher-level parties (6–8), add a second hag (standard green hag stats) and give the Hollowing legendary actions (1/round: move, Hollowing Gaze recharge check, or animate one additional shadow).