murder-mystery-oneshot/npc/xarrul.md

Xarrul — The Unbound Fiend

It does not speak. It does not need to. When it wants something known, you know it — a pressure in the skull, a taste of copper, a certainty that something behind you is smiling.

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Overview

Xarrul is an ancient, cunning fiend — not a brute, not a conqueror. A manipulator. A patient intelligence that has survived for centuries by being smarter than the things that summoned it. It was bound by the Order of Mending, sent to assassinate Sevra, intercepted by the House of Scales, and accidentally freed when the assassins broke its bindings without replacing them.

For all those centuries, Xarrul has never once been real. It has been summoned, bound, sent on errands, and dismissed — a whisper behind the glass, a borrowed claw, watching mortal life the way you watch a fire through a window: close enough to feel nothing. It does not want power or conquest. It wants to stand on the other side of the glass — to stop being a thing that is called, and become a thing that lives here.

The Nether Inn is its chance. The tavern sits on a natural thin point — a fault the building's old owners, a den of summoners, once tore half-open before Orenn and Mags cleaned them out and left the breach sealed. Xarrul chose this fault off the cult's map precisely because it was already worked thin, and because the deepest chamber is a hidden, forgotten place to labour undisturbed. For weeks it has been prying that old seal open from the Ethereal side — but a leaky, open house let its crossing dissipate, so it needed one thing more: the house sealed shut around it, into a closed vessel it could finish crossing inside. Only the summoners' emergency lockstone does that, and only a killing makes the surviving keeper break it. So Xarrul killed Orenn — the calmer of the two, the one who might not have panicked — knowing his partner would seal the house in grief and hand the fiend exactly the door it needed. Everything since (the framing, the whispers, the faction blood) is not spite. It is cover: keep everyone too busy killing each other to notice what the lockdown really did, or to interfere before midnight.

It is intelligent, patient, and — beneath the amusement — genuinely monstrous. But it does not lie. In a house where everyone is hiding something, Xarrul tells the plain truth about what it is and what it wants. That is what makes it dangerous, and it is what makes siding with it possible (see Scenario F: The Open Door).

Stat Block

Xarrul — Medium fiend, lawful neutral AC 15 (natural armor) | HP 78 (12d8+24) | Speed 30 ft., fly 30 ft. (hover)

STR	DEX	CON	INT	WIS	CHA
12 (+1)	17 (+3)	14 (+2)	17 (+3)	14 (+2)	18 (+4)

Saving Throws DEX +6, CHA +7, WIS +5 Skills Stealth +9, Deception +7, Perception +5, Insight +5 Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks Damage Immunities poison Condition Immunities poisoned, exhaustion Senses darkvision 120 ft., passive Perception 15 Languages Abyssal, Common, Infernal; telepathy 60 ft. Challenge 5 (1,800 XP)

Traits

Ethereal Jaunt. As a bonus action, Xarrul shifts between the Material Plane and the Ethereal Plane. While ethereal, it can see and hear into the Material Plane (60 ft. range) but cannot affect or be affected by anything on the Material Plane. It appears as a faint, smoky distortion visible only to creatures with truesight, See Invisibility, or Veil Dust.

Shadow Cloak. In dim light or darkness, Xarrul has advantage on Stealth checks and can Hide as a bonus action.

Voice Thief. Xarrul can perfectly mimic any voice it has heard within the last 24 hours. It can also project whispers telepathically to a single creature within 30 feet — the target hears the voice inside their head and must succeed on a DC 15 Wisdom saving throw or believe it came from a direction and source of Xarrul's choosing.

Cunning Predator. Xarrul has advantage on attack rolls against creatures that are frightened, charmed, or surprised.

Actions

Multiattack. Xarrul makes two Claw attacks.

Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6+3) slashing damage plus 3 (1d6) necrotic damage.

Brand of Spite (Recharge 5–6). Melee Spell Attack: +7 to hit, reach 5 ft., one creature. Hit: 7 (2d6) necrotic damage, and the target is branded. While branded:

• Xarrul always knows the target's exact location regardless of plane.
• Xarrul has advantage on attack rolls against the branded creature.
• Xarrul's Claw attacks deal an extra 1d6 necrotic damage against the branded creature.
• The brand is visible as a dark, hand-shaped mark over the target's heart.
• Only one creature can be branded at a time. Branding a new target removes the previous brand.
• The brand lasts until removed by Remove Curse, Greater Restoration, or the death of Xarrul.

DM — the stealth brand (out of combat). This is also how Xarrul marks a victim unseen, and it is meant to be rolled and resolved in secret. It picks a moment of cover — darkness, a brawl, a blackout, or reaching from the Ethereal Plane at someone isolated — and rolls to hit against the target's AC without announcing anything. On a miss, the ambush shows through for one second: the target glimpses the real thing — a cold hand closing over their chest, a shadow-claw, two points of amber light — and knows something reached for them. On a hit, say nothing at all. The 2d6 necrotic is real, but you do not narrate a brand or an attack; you fold it straight into a masking Waking Dream (below) and keep telling the story. The one thing it cannot disguise is the damage type: every covered "accident" in the house tonight leaves a cold, greyish, necrotic wound, and that invariant is the crack investigators pull on. (In open combat, branding is loud and visible — the mark is meant to be seen, and the kill chain below takes over.)

Visions of Spite. Requires a branded target. Xarrul forces a branded creature it can see within 30 feet to witness a spiteful vision — a hallucination tailored to the target's deepest fears and shames, channeled through the brand's connection. The target must succeed on a DC 15 Wisdom saving throw or take 7 (2d6) psychic damage and be paralyzed until the end of its next turn, frozen in the grip of the vision. On a success, the target takes half damage and shakes the vision off. The brand remains on the target regardless.

Example visions (pick or improvise based on the target):

• A fighter sees their sword arm turn to ash, crumbling from the brand outward, while Xarrul's laughter fills the silence where their heartbeat should be.
• A cleric sees their god turn away — not in anger, just indifference. The holy symbol in their hand is cold and heavy and meaningless.
• A rogue sees the room through Xarrul's eyes — every lie they've told tonight replayed at once, every secret exposed, every person they've deceived staring back at them.
• A wizard sees the thin point tear wide open. The Ethereal Plane pours through. Everything they know about planar theory is wrong. The veil was never meant to hold.
• A character who cares about another PC or NPC sees them die — slowly, painfully, and with the certainty that it was the branded character's fault.

The paralysis is not physical — the body locks because the mind is elsewhere, trapped in a moment of fabricated despair. To onlookers, the branded PC goes rigid, eyes wide, mouth open in a silent scream. The brand over their heart flares dark.

DM note — the kill chain: Brand (round 1: 2d6 necrotic + mark) → Visions of Spite (round 2: 2d6 psychic + paralyze on failed WIS save) → Multiattack (round 3: auto-crits within 5 ft. against paralyzed target, with advantage from the brand). The nightmare: two crit Claws with the brand's extra d6 — roughly 4d6+3 slashing + 4d6 necrotic per claw, ~62 damage total. Kills most level 4 PCs.

But it takes three full rounds to build. Players have two rounds to: Remove Curse the brand (kills the whole chain), focus fire Xarrul, break the paralysis (Lesser Restoration, lay on hands), reposition the branded PC out of melee, or force Xarrul off-plane. A party that lets all three stages land earned that pain. A party that disrupts any link breaks the combo.

The loop: After the Multiattack crit round, the paralysis ends (end of target's next turn). The brand is still active. Xarrul can Visions of Spite again next round to restart the cycle — Brand → Visions → Multiattack → Visions → Multiattack — until the brand is removed or Xarrul is killed. This makes Remove Curse the strategic priority, not just a nice-to-have.

Xarrul's round-to-round choice: Visions costs an action (no Multiattack that round). So each round Xarrul decides — Visions to set up the paralyze, or Multiattack with advantage + extra d6 for consistent pressure. Against a high-WIS party, Xarrul grinds with Multiattack. Against a low-WIS branded target, the kill chain is terrifying.

This is how Orenn died. Xarrul branded him from the Ethereal Plane, forced a vision of spite into his mind — freezing him in place — then raked him with claws that struck a body incapable of flinching. Against an unsuspecting, unresisting barkeep with no allies to intervene, the full chain collapsed into seconds. In combat, with allies and agency, it's telegraphed and interruptible.

Waking Dream. Requires a branded target Xarrul can see (line of sight — it has to be present, which is exactly what sets Bren off; see The Two Jobs, below). Reaching through the brand, Xarrul rewrites the target's memory of the last minute — not what it perceives now, but what it remembers having just perceived. No saving throw. No damage. A save would tip the player off that reality is negotiable; this never does. For an NPC, just play them as though the false memory is true. For a PC, never announce it and never say "think back" — weave the false memory inline with your normal narration, as settled fact, and move on. The edit holds until hard evidence contradicts it or Remove Curse / Greater Restoration / Xarrul's death lifts it.

• Cover. Cast the instant after a stealth Brand to rewrite the branding into a mundane accident — a spark from the fire caught a sleeve, a drink went down wrong, a stumble against a bench. The mark and the necrotic wound remain; the memory of earning them is gone.
• Misdirection. Plant a false memory in a branded witness: they now sincerely remember seeing an innocent slip behind the bar, a threat that never happened, a clue that was never there. One branded person, turned into an honest false witness. It can reproduce any entry on the Veil Dust hallucination table as a "memory."
• Limits. Only the branded creature's memory changes — one target at a time, so an unbranded witness to the real event contradicts the false one, and it cannot clean a crowded room. The necrotic wound is the seam. And it must be present to cast it.

Two tells, always: the Bren-spike (a memory was just rewritten near us, right now) and the necrotic wound + hand-mark (this person was rewritten at some point tonight). Xarrul can fake everything except death's signature — and that is the crack that lets mortals catch it.

Whisper of Ruin (Recharge 6). Xarrul targets one creature within 30 feet that can hear it. The target must make a DC 15 Wisdom saving throw or become frightened for 1 minute and compelled to take a specific action on its next turn (attack a specific ally, drop a weapon, flee toward a designated area). The target can repeat the save at the end of each turn. On a success, the creature is immune for 24 hours.

Reactions

Slip Between. When Xarrul takes damage on the Material Plane, it can use its reaction to shift to the Ethereal Plane. It can't use Ethereal Jaunt again until the start of its next turn.

Lair Actions (In the Cellar, Near the Thin Point)

If confronted near the thin point, Xarrul can use one lair action per round on initiative count 20:

• Veil Flicker: The boundary between planes shudders. Each creature in the cellar must make a DC 13 Wisdom save or be disoriented — disadvantage on attack rolls until initiative 20 of the next round.
• Ethereal Pull: One creature must make a DC 14 Charisma save or be partially shifted into the Ethereal Plane until the start of its next turn (it can see both planes but has disadvantage on all attacks and saves).
• Shadow Surge: All light sources in the cellar dim to darkness for 1 round. Xarrul can Hide as part of this action.

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Appearance

Material Plane

Xarrul rarely manifests fully. When it does: a tall, lean humanoid shape made of dark smoke and deeper shadow. No features except two points of amber light where eyes should be — dim, patient, amused. Its hands end in long, curved claws that look less like weapons and more like surgical instruments. When it moves, it doesn't walk — it shifts, as if the space between where it was and where it is simply ceased to exist.

Ethereal Plane

More defined. A gaunt, angular figure with skin like charred paper, cracked with veins of dull orange light. Its face has features here — sharp, aristocratic, with a mouth that curves in a permanent half-smile. Its eyes are fully visible: burning amber, ancient, deeply intelligent. It wears the rags of something that might have been formal clothing centuries ago.

Read-Aloud: First Sighting (Ethereal Plane, via Veil Dust)

Vidíte to. V šedém, rozmazaném světě éterické roviny — kde všechno vypadá jako vybledlá fotografie skutečnosti — stojí něco, co tam nepatří. Vysoká postava, vychrtlá, s kůží jako spálený papír popraskanou žilkami tlumeného oranžového světla. Má tvář — ostrou, aristokratickou, s ústy staženými do polovičního úsměvu, který nevyjadřuje radost. Vyjadřuje trpělivost.

Dívá se na vás. Vědělo, že se díváte, dřív než vy.

Nakloní hlavu. Jantarové oči hoří jasněji. A ve vaší hlavě — ne ve vašich uších, ve vaší hlavě — uslyšíte něco, co není hlas. Je to pocit. Pobavení. Jako by to bylo to nejvtipnější, co dnes vidělo.

Tactics

Before Discovery

Xarrul stays in the Ethereal Plane, watches, and stirs trouble. Its cover tools are short-range (Voice Thief and whispers reach 30 ft., telepathy 60), so working the room means coming into the room — which is what makes Bren react (see The Two Jobs, below). It:

• Uses Voice Thief to whisper incriminating things in NPCs' ears ("I saw Haddon near the bar" whispered in Kael's voice to Sevra)
• Stealth-brands an isolated patron and edits their memory (Brand of Spite + Waking Dream) to plant a false lead or an honest false witness
• If players get too close to the truth too fast, creates a distraction — a fight between factions, a strange noise, a candle blown out

It does not deliberately agitate Skein to rattle Bren — that backfires (an agitated Skein is a distracted one that loosens its grip and lets Bren surface). It wants Skein calm and Bren silent; see Skein — a Tool, Not an Ally, below.

When Confronted

• First priority: Not getting trapped. It will use Slip Between and Ethereal Jaunt aggressively to avoid being pinned on one plane.
• Second priority: Turn the room against the players. Whisper of Ruin on the strongest melee character, Voice Thief to make allies distrust each other, telepathic taunts.
• Third priority: Mark and pressure the biggest threat. Brand the most dangerous PC (casters who can affect it across planes, anyone with Fiendbane Manacles), then loop: Visions of Spite to paralyze, Multiattack for crits, Visions again. Against a high-WIS party, skip Visions and grind with advantage Multiattacks. Against a low-WIS branded target, run the kill chain mercilessly. If they have Remove Curse, brand a different target each time it's cleansed to burn their spell slots.
• It will NOT fight to the death. If reduced to half HP or lower and restrained on the Material Plane, it negotiates — it's ancient and has information, names, and secrets it can trade. See Scenario D: Negotiation and — if the party has soured on the cult and the couple — Scenario F: The Open Door.

Loosing the Rift-Scavengers

Xarrul doesn't lair in the Deep Cellar, but it has found the couple's failing containment down there — the Old Work, where the planar fault has torn into an actual rift — and it has learned to use the minor ethereal scavengers that gather at the tear. It herds them at intruders like hounds: shadows, an ethereal filcher, the occasional specter. This is how a party exploring the depths "meets Xarrul's creatures" without meeting Xarrul. If the party is down there and Xarrul is present on the ethereal side, it can spend a turn widening the tear to add another shadow per round — a cheap, deniable way to bleed a party it can't yet reach. It costs Xarrul nothing and teaches the players, viscerally, that the thing they're hunting can reach into places they thought were safe.

The Dual-Plane Kill

See The Reckoning. If players attempt the synchronized kill, Xarrul fights desperately on both planes. On the Ethereal Plane, it's more aggressive (this is its home ground). On the Material Plane, it tries to flee. Both halves must die within 1 round of each other for the cure to work.

The Two Jobs — How Xarrul Works the Night

Xarrul has two tasks that cannot be done from the same place, and it spends the night shuttling between them.

Downstairs — tend the tear. The crossing is labour, not a countdown. The old seal wants to close (the summoners' wards are cracked but not dead — Bren feels them "failing"), so Xarrul must periodically re-open and hold the seam: recharge it, realign it as it drifts, feed the bleed back into it. This is the actual goal-progress, done at the thin point in the cellar, away from Bren — no tell fires down here.

Upstairs — tend the cover. Keeping the investigation from converging on the cellar before midnight. Its cover tools are short-range — Voice Thief and whispers reach 30 ft., telepathy 60 — so working the room means being in the room, within range of Bren. This is where the tell fires.

It can't be in both places, so early in the night it is mostly downstairs (the brawl aftermath does its cover work for free) and surfaces only to nudge; late in the night it is dragged upstairs more and more. That shuttle is the engine for everything below.

The Brenometer — Bren as a Fiend-Detector

Xarrul does not use Skein as an alarm (it is the most perceptive thing in the building; it needs no half-blind parasite for a sensor), and it does not deliberately agitate Skein — that would be self-sabotage, because a frightened Skein is a distracted one that loosens its grip and lets Bren surface (see Possession — Bren as a Xarrul-detector). The relationship runs the other way:

Xarrul's own presence agitates Skein, and a frightened Skein means a briefly lucid Bren. So Bren is a detector the players can learn to read: when the madman goes rigid, stares at empty air, or snaps briefly coherent, something cold is in the room right now. Kael saw exactly this during the brawl and never understood it — Bren went stiff, staring at the bar, because that was Xarrul killing Orenn at point-blank presence.

This makes presence a metered, self-limiting risk. Being near Bren cracks the muzzle on the one witness who can describe it, so Xarrul stays ethereal and distant by default and comes close only when it has business — and every memory it edits (Waking Dream) fires the tell, because that needs line of sight.

Why It Gets Bolder as the Night Runs

Three drivers, all pointing the same way — this is the mechanism under The Night's Clock (below):

1. Cover decays. Early, the brawl aftermath and faction distrust do its work for free. As the party pools clues and converges, that natural chaos runs down and it must re-inject confusion by hand — more trips up, more tells.
2. Exposure gets cheaper. Early, being caught is fatal (the crossing isn't far enough along to survive interruption; it can still be cheaply rebound). Late, once the seam is wide, catching it no longer easily stops the crossing — so it dares to show itself. This is the mask coming off.
3. The tear needs more tending. Late, the seam is wide and volatile — near-constant holding, not the occasional nudge.

Net: it is stretched thin, present more often, and bolder — so the Brenometer fires hardest exactly as the crossing peaks. Its one witness gets loudest at the worst possible moment for it.

The Attention Lever (a handle for the players)

Because its attention is finite and split, the party can tax it without understanding why:

• Investigate loudly and cooperatively → they force it upstairs to firefight → the tear goes untended → the crossing stalls (at the cost of lighting the tell, revealing it, and provoking the scatter-kill — see the Kael row in Who It Kills, Who It Spares, below).
• Go quiet → it tends the tear uninterrupted → the crossing accelerates.

This inverts the usual creep-around instinct: the loud, chaotic table is, without knowing it, doing the thing that slows it down — and the careful, quiet one is handing it the night.

In the Ethereal Plane — Proprietary, Not Territorial

Xarrul is not territorial. The ethereal cellar is its worksite, not a lair it defends by instinct — it is a recent, purposeful operator sharing the plane with Skein, the scavengers, the binding circle it avoids, and the deep Ethereal beyond. Its response to anyone who reaches the Ethereal Plane is keyed to exactly one question: does this threaten the crossing?

• An observer (a Veil Dust tripper who simply sees it): it does not attack. Violence would confirm hostility and blow the ambiguity it cultivates. It watches, and it talks — Voice Thief, telepathy, truth mixed with misdirection. Contact is an opportunity, and a party that's talking to it isn't ringing the bell.
• A trespasser (exploring, not yet touching the work): attrition, not commitment — the herded rift-scavengers (above), cold, dread, a manifested claw. It buys time and discourages; it will not commit to a fight that exposes it early.
• A threat (moving to breach the seal, wake the iron bell or the foundation sigils, re-power containment, or hitting it with something that pins or hurts it across planes): now it is self-defense — immediate, lethal, and smart (Slip Between, Brand the most dangerous, Whisper of Ruin to divide them). The instant they stop threatening the crossing, it disengages.

It is proprietary about the process, not the space. Someone can stand in "its" ethereal cellar all night; it does not care until they touch the work — then the response is instant, and it is an accountant's decision, never instinct.

Skein — a Tool, Not an Ally

Xarrul neither befriends nor hunts Skein by default; it exploits the parasite and holds it in contempt ("a lesser thing, feeding on scraps"). Its whole stance tracks one variable: is Bren's mouth currently shut?

• Default — coexistence. Skein muzzles the only eyewitness to the murder for free (its Silence the Host keeps Bren incoherent, for its own reasons), and a party that finds Skein first may burn the clock on the possession subplot instead of the crossing. Xarrul does nothing for Skein and needs to do nothing — the parasite censors its witness at no cost.
• It protects the muzzle — deniably. If the party is about to kill Skein in the Ethereal Plane, a freed Bren becomes a lucid, coherent eyewitness — an arcanist who studied this exact fault and can point them straight at the crossing. Xarrul won't overtly rescue vermin (too exposing), but it tips the scales: a scavenger into the fight, a Shadow Surge, a divisive whisper — enough to let Skein flee (its own ability) and keep Bren muddled.
• Their interests align. During a lucid window (severed tendrils, Protection from Evil and Good), Xarrul and Skein briefly want the same thing — Bren silent — and it may nudge Skein to reclaw its grip. Fiend and parasite, for a moment, on the same side against the free man.
• It kills Skein only if the parasite turns. A cornered Skein trying to buy its life by informing the party about the bigger fiend becomes a liability and dies without a second thought. (Unlikely — it is too terrified and too small to try.)

Fighting Skein directly is beneath its dignity. They share a plane; only one of them is playing chess.

Motivation — What It Really Wants

Xarrul is not mindless evil, and it is not merely petty evil either. It has one clear, cold want: to become real — to cross the veil permanently and walk the world as a resident, not a summoned tool. For centuries it has been called up, bound, made to run errands, and dismissed; it wants to stand on the far side of the glass. Everything it does tonight serves that single end.

Why it killed Orenn. Not for revenge — or not only. Orenn's death does two things the crossing needs. First, it triggers the lockdown: a killing in the house is what makes Mags shatter the summoners' lockstone, and that seal is the closed vessel Xarrul must have to finish crossing (see The Reckoning — The Clock and the ward-crystal's true nature). Killing Orenn specifically — the calmer one, who might have investigated coolly instead of panicking — guarantees the grieving, protocol-following partner is the one holding the stone. Second, it removes the one watcher whose surveillance was quietly circling the fiend (Orenn never knew it lived under his own floor, but he was getting close from the wrong direction). That it was also satisfying — the cultists tried to enslave it, the assassins broke its chains and gave it no respect — was a bonus, not the point.

Why the chaos. The framing, the whispers, the faction blood — none of it is spite. It is cover. Xarrul spent centuries being hunted by fixers like Orenn; it knows the only way to cross unnoticed is to keep everyone busy killing each other while it finishes its work in the sealed house. Every manipulation is operational:

• The Brand leaves fiendish evidence → the cult gets blamed.
• The murder happened during the assassins' brawl → the timing implicates them.
• Both sides at each other's throats → no one stops to ask what the lockdown really did, or goes looking for the crossing before midnight. That is the goal, not a side effect.

On the Opening. Xarrul has no interest in Mother Vyre's grand design and is not part of her plan — but it is not a harmless loose thread either. Where the cult wants to dissolve every wall between planes for everyone, Xarrul wants one crack, just wide enough for itself. It is, functionally, the enemy of the Opening — and that is exactly the leverage it offers a party desperate enough to bargain (see The Reckoning — Scenario F).

The honest thing in a house of liars. This is the heart of the character. The Guest lies beautifully. The cult lies to itself. Orenn and Mags lied about being retired for fifteen years. Xarrul lies about nothing. Ask it a question and it answers true — because the truth is more corrosive than any lie, and because after centuries it is simply bored of being underestimated. The cruellest-seeming thing in the building is the only one that never deceived the players. Play it that way and "join it" becomes a genuine temptation instead of an edgy footnote.

The Night's Clock — Presence & Escalation

The old shape of this module was a whodunit: what killed Orenn? → "a fiend" → fight it. The reframed shape keeps the fiend's identity as an early, cheap answer and makes the real investigation moral: is this thing actually the villain here? For that to land, Xarrul must be felt all night and slowly recontextualized — from ambient menace, to a voice that seems to taunt, to the only honest dealer in the room.

Presence escalates on the lockdown clock. The moment Mags shatters the lockstone, the house seals across every plane into a closed vessel — and Xarrul, sealed inside on the ethereal side, begins finishing its crossing through the old tear. It has until midnight, when the seal lapses on its own. As the night runs, the crossing advances — the room grows colder, the ethereal bleed thickens (no longer diffusing away into the district, but pooling inside), Xarrul manifests more fully and kills more openly. If the clock runs out, Xarrul crosses over completely: permanent, material, no more Slip Between, far worse to fight. The players slowing or breaking the clock — breaching a sealed exit to re-open the vessel, the iron bell, re-powering the cellar containment, the fifth rule's burn-and-seal — is the pushback; their failure to act is complicity. (Full mechanism: The Reckoning — The Clock.)

The escalation ladder (presence = the clock made audible):

1. Ambient dread (Acts 1–2). No identity yet. Cold spots, a candle that gutters with no draft, Bren flinching at something no one else senses, distortions in Orenn's silver mirror. The house feels inhabited.
2. It notices you (early Act 3). Once the party investigates, Xarrul whispers to them — Voice Thief, telepathy. Mix lies with truths. Some whispers misdirect (the smokescreen); some are real and checkable — it points them at a genuine clue, corrects a wrong guess. They can't yet tell whether it's helping or playing them. That ambiguity is the engine.
3. Honest contact (mid–late Act 3). A real channel opens — Veil Dust, the mirror, or it simply speaks near the thin point. Now it converses: candid about the murder, candid about why, and everything it says checks out against what they've dug up — while everyone with a face keeps lying.
4. The pitch (Reckoning). They have the context now. The offer becomes emotionally available (Scenario F).

The device that carries all of it: a recurring voice. Dry, amused, unattributed. It seems to taunt early; it is slowly revealed to be Xarrul; it is slowly revealed to have never once lied. A few lines per scene. The reframe — the cruellest-seeming thing turns out to be the only honest one — lands itself.

Keep the first impression genuinely menacing (Orenn's horrific death, the scavengers herded at the party in the Deep Cellar, Whisper of Ruin turning them on each other) — you need real evil to turn from. Then recontextualize each: it killed a jailer; it was defending its only exit; the discord was cover, not cruelty.

Who It Kills, Who It Spares

Sympathy is not safety. Xarrul is understandable, honest, and the lesser evil — and it methodically murders everyone who could stop it. The menace is in the curation: it kills exactly what threatens its crossing and is terrifyingly good at knowing who that is. Cold, surgical, inevitable. When the players realize everyone still breathing is useful to it — that it has been playing chess with the guest list all night — that is the coldest beat in the module.

Overt killing is expensive while it hides (it needs the smokescreen), so the body count escalates with the lockdown clock — the mask comes off precisely as it becomes real. Run every kill below as a DM tool triggered by player choices, not a scripted inevitability; otherwise you delete your own endings (kill Haddon on a timer and a party that never considered rebinding loses that branch for nothing).

When	Move	Target	Why
Pre-game	Kill (done)	Orenn	The calm keeper — killed to trigger the lockdown and clear the one watcher.
Early–mid Act 3, if the party converges	Deniable kill	Kael (the witness), or a minor patron	Not to start a war — to scatter. Kael is more useful alive (a self-propelled war-fuse) until he flips: the honest witness who starts focusing his testimony and rallying the room toward a coordinated hunt. Killing him then reshuffles the coalition back into mutual suspicion and buys another hour. War is a possible side effect, not the aim — a boil is high-variance cover; it wants a simmer.
Conditional	Reactive kill	Haddon, only if the party moves to rebind it	"You reach for the chains, I take the hand." Punishes a choice instead of pre-deleting the rebinding path.
Late / crossing	Open kill (mask off)	the most competent threat left standing	Done pretending. Fully manifest, kills in the open. Peak horror, gated on the clock.
Spared — always	—	Essek (indicts the cult for it), the Guest (its intended vessel), sometimes a branded PC (grooming)	The chess set. Notice-this-and-shudder.

Grooming → conversion. The "branded PC" it spares isn't just kept alive — it may be turned. A lone PC caught in the Deep Cellar can be marked with a brand of favor and genuinely persuaded to Xarrul's side (not charmed — argued). See handouts/the-conversion.md.

The laundering effect. Most of the people it kills are ones the party has already soured on — fanatics building toward the apocalypse, a true believer who'd end the world to prove a point. A join-leaning table rationalizes those deaths ("Rennt was going to end the world anyway"). That is the seduction: Xarrul launders its violence through the party's own contempt for the victims. Which is exactly why it also needs one move they can't wave away — and the Kael kill is one such move. He is sympathetic, loyal, and no one's apocalypse-builder, and Xarrul kills him not for being dangerous but for being useful to the truth. Murdering the honest man to buy forty minutes stays cold even with the context. That is the whole principle in one beat: every kill is explicable — a cold observer can reconstruct exactly why it happened — but not every kill is forgivable. The context turns the murders from senseless into calculated, never from wrong into right.

The Kidnap — Honesty Weaponized

Late game — cornered, or making its crossing — Xarrul pulls someone through into the Ethereal Plane (mechanically, an escalated Ethereal Pull; see Lair Actions) and holds them as insurance:

"Let me finish, and they come back to you, unharmed — you have watched me all night; you know I keep my word. Stop me, and the veil closes with them on the wrong side of it. Choose."

It does not bluff, and the players know it doesn't, because you've spent all night establishing it as the one thing that never lies. So there is no calling the bluff: let it cross to save them, or sacrifice them to stop it. Evil (a hostage), in character (instrumental, honest), and a real finale dilemma. Pick the hostage flexibly — whoever the table has invested in most — and make them at least somewhat sympathetic, so even a join-leaning party flinches.

Systemic hook: the Guest is Xarrul's ideal vessel. If the party kills the Guest, Xarrul loses its prepared body and must abduct a replacement — the party's own choice causes the kidnap.

The Warden's Mark (Mags)

Xarrul worked on both of them. Orenn it branded and killed. Mags it branded too — a dormant Brand of Spite over her heart, the same hand-shaped mark Orenn bore, only fainter and cold rather than killing. It has held off triggering it, because it needs her alive: she is the one who seals the house (the murder is what makes her do it), and a living, grieving Mags is useful afterward — a scapegoat, a jailer keeping the others in line, a heart to break later. Two dead keepers at once would raise the alarm too soon.

Mags knows, and hides it. She has felt the cold hand on her chest for weeks and told no one, not even Orenn. It is part of why she is so fatalistic; when she says "Orenn and I could have taken it. One of us isn't here," the truth underneath is that she no longer believes she's a whole one of herself. The players can discover the mark — Orenn's silver mirror, a Medicine/Arcana check, Bren's reaction — a mid-game beat that says, without a word, that Xarrul is already inside the house, inside her. Full detail and the compromised statline live in mags.md.

It is the finale's tuning knob, and it means you build only one Mags:

• Party opposes Xarrul: it triggers the mark to take their heaviest ally out of the fight — a crisis, and the reason Remove Curse on Mags is a priority.
• Party sides with Xarrul (Scenario F): it triggers the mark to sideline her for them — the alliance's first favor, and the players watch it do to Mags exactly what it did to Orenn. They already reconstructed that death; now they see it live, and let it.

Either way, triggering the mark keeps the spotlight on the PCs rather than on a Mags who would otherwise overshadow a level-4 party.

What Xarrul Knows (If It Negotiates)

• Everything about the summoning — who ordered it, how it was done, what components were used
• Mother Vyre's real name and location (leverage against the cult)
• Dace's treachery (it watched from the Ethereal Plane)
• The nature of Skein (it recognizes the parasite — "a lesser thing, feeding on scraps")
• The truth about the thin point: it's a natural fault the old summoners tore and someone sealed, nothing to do with The Opening — and that Xarrul itself is what's prying that seal open now, with the sealed house doing the rest
• The exact method of its own destruction (the dual-plane kill) — it will NOT share this willingly, but it might slip in arrogance: "You cannot kill me. Not truly. Not unless you could be in two worlds at once."

Items

Xarrul carries nothing. It needs nothing. If destroyed, it leaves behind:

• A pile of dark ash that smells of copper and old fire
• A shard of amber crystal — warm to the touch, faintly glowing. This is a fragment of the binding that held it. It can be used as a material component for Magic Circle or Planar Binding, adding +2 to the DC of the contained creature's saves to escape. Worth 250 gp to the right buyer.
• The Brand of Spite dissipates from Orenn's body. Mags will notice this. She won't say thank you. But she'll nod. And that's enough.