The Fortress in the Forest: A One-Shot Adventure

Adventure overview

The adventurers are escorted to the edge of the Silver Woods and charged with finding the Bristle Stronghold. Their route takes them through dangerous forest, into swamp, and past a green hag who knows more than she first reveals. At the fortress, the remains of an earlier expedition and a summoning ritual point toward cult activity. Removing the ritual book calls Mezgarriath, a servant of Belphegor, who returns each night until the adventurers complete the unsummoning ritual.

Format	Details
Length	One 4–5 hour session
Structure	Two acts: expedition and exploration, followed by attack and unsummoning
Characters	Eight pregenerated character concepts are included; the adventure assumes a five-character party
Primary locations	The Silver Woods, the hag’s swamp hut, and the Bristle Stronghold
Resolution	Find a bell, protect three ritual participants for 1 minute, and complete the unsummoning ritual

Running the one-shot

The adventure has a direct spine: reach the stronghold, discover the summoning book, survive Mezgarriath’s demand for its return, and perform the unsummoning ritual. The character agendas create competing priorities around the expedition’s evidence, the cult, the maps, combat glory, and exploration. Keep those agendas visible, but do not let them obscure the central countdown to nightfall.

Adventure sequence

Act	Scene	Purpose
I	Into the Woods	Receive the League’s charge and cross the Silver Woods.
I	Harbinger	Choose whether to bargain with, bypass, or fight the hag.
I	Arrival	Explore the stronghold and trigger the threat.
II	First Night Discovery	Learn that killing Mezgarriath does not end the summoning.
II	Unsummoning	Find the bell and defend the ritual until it is complete.

Act I · The expedition

Scene 1 · Into the Woods

Crossing the forest

Party composition	Checks per half day	On a failure
With the ranger	One DC 12 Wisdom (Survival) check	Trigger a random encounter.
Without the ranger	Two DC 12 Wisdom (Survival) checks	Trigger a random encounter for each failed check.

Use the Random Encounter Table at the end of the adventure whenever an encounter is triggered.

Scene 2 · Harbinger

As the adventurers progress, the forest gives way to swamp. A character who succeeds on a DC 12 Wisdom (Perception) check notices the change before it becomes obvious and also spots signs of other humanoid activity in the area.

The choice at the hut

• Go around. The detour adds one night to the journey as the party slogs through the swamp. The adventurers cannot sleep and each gains 1 level of exhaustion.
• Approach. Crossing the fence line triggers a Guards and Wards spell that alerts the hag to the adventurers’ presence. She immediately challenges them.
• Attack, insult, or steal. If the adventurers attack the hag, insult her, or she catches someone stealing, she attacks and the three Darklings defend her.

Encounter: Silver Woods — Green Hag and Darklings

Bargaining with the harbinger

The hag responds to flattery and gold. Use the following Charisma (Persuasion) checks for what she is willing to reveal.

Check	Information
DC 12	Others have passed through the forest: the Monarch’s Expeditionary Force and a small group of humans leading others in chains.
DC 17	She reveals a route through the forest that cuts one full day from the journey.

Scene 3 · Arrival

Exploring the grounds

A character who succeeds on a DC 16 Intelligence (Investigation) check near the stable finds the skeleton of a horse. A rotting leather satchel remains on the bones. Inside is the oil-wrapped diary of the commander of the Monarch’s Expeditionary Force.

The diary records the force’s entire journey and includes detailed maps. Its final pages note that the expedition encountered a group of cultists and their slaves.

The first tower: first floor

• Summoning room. The room is mostly empty except for a summoning circle. A book lies at its center beside the nub of a burned-out candle. The book describes a ritual for summoning Mezgarriath, a servant of Belphegor, Prince of Sloth. Taking the book causes Mezgarriath to attack at nightfall.
• Stairway. Spiderwebs fill the stairs. The adventurers must cut or burn through them to continue upward.
• Storage room. A character who succeeds on a DC 14 Intelligence (Investigation) check finds several loose pages and scrolls, along with a large leather tube holding a massive map.

The first tower: second floor

The second floor contains the kitchen, barracks, dining area, and armory.

• Kitchen. A candle can be found here if the party does not already have one for the unsummoning ritual.
• Armory. A passage once connected the two towers, but it has collapsed. There is no easy route through to the second tower.
• Outside route. From the armory, the adventurers can see the branches of the nearby tree reaching the second tower’s window.

Act II · The thing summoned

Scene 1 · First Night Discovery

At nightfall, Mezgarriath appears in the courtyard before the tower and demands that the adventurers return the summoning book. He moves toward the book, fighting any significant threat that prevents him from reaching it.

Mezgarriath can raise as many as 12 zombies and can summon Shadow Gaunts to help recover the book. The first attack uses only the forces listed above.

Killing Mezgarriath does not end the summoning. His body dissolves into the earth, and he returns the following night. He continues to return until the adventurers complete the unsummoning ritual.

Scene 2 · Unsummoning

The ritual in the book can unsummon Mezgarriath, but it requires a candle, a bell, three participants, and 1 uninterrupted minute. The candle can be found in the second-floor kitchen if the adventurers do not have one. The bell is hidden in a storage chest in the second tower.

Reaching the bell

The collapsed passage in the armory prevents an easy crossing between towers. The visible branches of the tree outside lead toward the second tower’s window. Inside the second tower, the adventurers can search the storage chests and find the bell.

Performing the ritual

1. Three adventurers begin the ritual and must continue it for 1 minute.
2. The remaining two adventurers defend them against two waves of Shadow Gaunts. Each wave contains 3 gaunts.
3. If a ritual participant is attacked, that character must succeed on a DC 10 Constitution saving throw or the ritual is disrupted.
4. When the ritual is completed, the Shadow Gaunts disappear and Mezgarriath is unsummoned.

Ending the adventure

The adventure ends when the ritual is completed and Mezgarriath is unsummoned. The party can return with the maps, diary, loose pages, scrolls, and any other documents they recovered for the League of Exploration and Maps. Resolve each character’s personal goal according to the evidence, combat events, exploration, and choices that occurred during play.

Pregenerated characters

The source provides eight character concepts for a five-character party. Each has a practical feature summary and a personal goal that points toward material already present in the adventure.

Human fighter · Champion

CHAOTIC GOOD SOLDIER

Notable equipment and features

• Adamantine chain shirt: immunity against critical hits.
• +1 battleaxe.
• Improved Critical: weapon attacks score a critical hit on a roll of 19 or 20.

Roleplaying

• Trait: I face problems head-on. A simple, direct solution is the best path to success.
• Trait: I’m always polite and respectful.
• Ideal: Live and Let Live. Ideals aren’t worth killing over or going to war for.
• Bond: I would still lay down my life for the people I served with.
• Flaw: I have little respect for anyone who is not a proven warrior.

Dragonborn barbarian · Path of the Totem Warrior

TRUE NEUTRAL OUTLANDER

Notable equipment and features

• Brass dragon breath weapon: fire.
• +1 warhammer.
• Bear Totem: while raging, resistance to all damage.
• +2 hide armor.

Roleplaying

• Trait: I have a lesson for every situation, drawn from observing nature.
• Trait: I was, in fact, raised by wolves.
• Ideal: Glory. I must earn glory in battle, for myself and my clan.
• Bond: My family, clan, or tribe is the most important thing in my life.
• Flaw: I remember every insult and nurse a silent resentment.

Dwarf rogue · Scout

NEUTRAL GOOD BOUNTY HUNTER

Notable equipment and features

• +1 leather armor.
• +1 shortbow.
• Skirmisher: as a reaction when an enemy ends its turn within 5 feet, move up to half your speed without provoking opportunity attacks.

Roleplaying

• Trait: I blow up at the slightest insult.
• Trait: I always have a plan for what to do when things go wrong.
• Ideal: Freedom. Chains are meant to be broken, as are those who would forge them.
• Bond: I’m guilty of a terrible crime and hope I can redeem myself.
• Flaw: I turn tail and run when things look bad.

Elf sorcerer · Shadow Magic

NEUTRAL EVIL COURTIER

Notable equipment and features

• +1 sling.
• Ring of protection.
• Strength of the Grave: when non-radiant, non-critical damage reduces you to 0 hit points, make a Charisma save (DC 5 + damage taken). On a success, drop to 1 hit point instead; once per long rest.

Roleplaying

• Trait: I talk at length about my profession.
• Trait: Anything worth doing is worth doing right; I am a perfectionist.
• Ideal: Community. Civilized people must strengthen the bonds and security of civilization.
• Bond: I owe my guild a great debt for forging me into who I am.
• Flaw: I would kill to acquire a noble title.

Gnome wizard · School of Illusion

CHAOTIC NEUTRAL CLOISTERED SCHOLAR

Notable equipment and features

• Wand of magic missiles.
• Ring of protection.
• Gnome Cunning: advantage on Intelligence, Wisdom, and Charisma saving throws against magic.

Roleplaying

• Trait: I use polysyllabic words to convey great erudition.
• Trait: I claim to have read every book in the world’s greatest libraries.
• Ideal: No Limits. Nothing should fetter the infinite possibility inherent in existence.
• Bond: My life’s work is a series of tomes about a specific field of lore.
• Flaw: I cannot keep a secret to save my life—or anyone else’s.

Half-orc bard · College of Lore

CHAOTIC EVIL ENTERTAINER

Notable equipment and features

• +1 longsword.
• +1 padded armor.
• Relentless Endurance: when reduced to 0 hit points but not killed, drop to 1 hit point instead; once per long rest.

Roleplaying

• Trait: I’m a hopeless romantic, always searching for that special someone.
• Trait: I love a good insult, even one directed at me.
• Ideal: People. Seeing smiles when I perform is all that matters.
• Bond: I will do anything to prove myself superior to my hated rival.
• Flaw: A scandal prevents me from going home; that kind of trouble follows me.

Tabaxi ranger · Gloom Stalker

NEUTRAL EVIL CRIMINAL

Notable equipment and features

• Cloak of elvenkind.
• +1 longbow.
• +1 scale mail.
• Feline Agility: double your speed for a turn; recharge after you spend a turn moving 0 feet.
• Dread Ambusher: add Wisdom modifier (+2) to initiative; gain 10 feet of speed on the first turn; when taking the Attack action that turn, make one additional attack dealing +1d8 damage on a hit.

Roleplaying

• Trait: I do not pay attention to risk. Never tell me the odds.
• Trait: I would rather make a new friend than a new enemy.
• Ideal: People. I’m loyal to my friends, not to ideals.
• Bond: Someone I loved died because of my mistake. That will never happen again.
• Flaw: When I see something valuable, I can think only about stealing it.

Tiefling cleric · Tempest Domain

LAWFUL NEUTRAL HAUNTED ONE

Notable equipment and features

• +2 mace.
• Restorative ointment.
• Potion of invulnerability.
• Wrath of the Storm: when a visible creature within 5 feet hits you, use your reaction to force a DC 14 Dexterity save; deal 2d8 lightning or thunder damage, half on success.
• Channel Divinity — Destructive Wrath: deal maximum lightning or thunder damage instead of rolling.

Roleplaying

• Trait: I spend money freely and live fully because tomorrow I might die.
• Trait: I refuse to become a victim or allow others to be victimized.
• Ideal: I help those in need, no matter the personal cost.
• Bond: I would sacrifice my life and soul to protect the innocent.
• Flaw: I speak to spirits no one else can see.

Random Encounter Table

A random encounter is triggered when a required Survival check fails. The ranger can also trigger one by venturing out of sight of the group, and the ranger’s personal agenda notes that sleeping in the forest or wandering more than 30 feet from the group can trigger an encounter.

d6	Encounter
1	Elk
2	Brown bear
3	Dryad
4	Saber-toothed tiger
5	Redcap
6	Swarm of stirges

Adventure checklist

• Introduce Zerikoth Devers and the League’s recovery terms.
• Resolve navigation through the Silver Woods.
• Present the hag’s hut and the cost of going around.
• Place the expedition diary, summoning book, loose papers, scrolls, and massive map.
• Trigger Mezgarriath at nightfall when the book is taken.
• Make the bell discoverable in a storage chest in the second tower.
• Run two waves of 3 Shadow Gaunts during the 1-minute ritual.
• Resolve the party’s return and each personal goal.

THE STYGIAN LABYRINTH
Guild of Lost Lore · Campaign / Adventure Content