Dungeons & Dragons - The Harrowing 5e Conversion

by Stephen Daniele

Later this year, I'm going to be running four old D&D adventures for my group, converted to 5th edition rules. All of these adventures were written by my favorite RPG author, Monte Cook:

• (lvl 12) A Question of Ethics
• (lvl 12) The Harrowing (from Dungeon Magazine #84)
  
• (lvl 14) Mysteries of the Dead Gods (based on an article Monte wrote in Dragon Magazine #240)
• (lvl 14) Demon God's Fane
• (lvl 16) A Paladin in Hell
• (lvl 18) Labyrinth of Madness

I posted the conversion of A Question of Ethics, so now we're going to jump in to The Harrowing!

Where to Buy: You can buy this adventure on amazon. Or you can get a .pdf version of The Harrowing for $5 on the Paizo site.

I figured it might be useful to post my conversion notes, both for my own reference and in case you ever to decide to run one of these adventures for your own group.

The original adventure is for 15th level characters. This conversion is for 12th level characters, as that is the level my group is at.

General Notes

We'll use the damage expression guidelines from the DMG. Levels 11-16:

• Setback: 4d10
• Dangerous: 10d10
• Deadly: 18d10
  

We'll also use the trap guidelines from the DMG:

• Setback: Save DC 10-11 Attack Bonus +3 to +5
• Dangerous: Save DC 12-15 Attack Bonus +6 to +8
• Deadly: Save DC 16-20 Attack Bonus +9 to +12

Magic Items: 3rd edition adventures give the villains a lot of magic items mostly to adjust for the math in that edition. 5th edition doesn't really need that, so I've discarded most of the stat-boosting magic items from the monsters. For example, one male drow has +1 armor, a +1 shield, and a +1 short sword. If I kept all those in this adventure, the group would end up with a mountain of +1 items.

To scale encounters, I am using kobold fight club.

5e Drow Stats

This is a fantastic opportunity to use the drow featured in Mordenkainen's Tome of Foes:

• Drow Arachnomancer CR 13
• Drow Favored Consort CR 18
• Drow House Captain CR 9
• Drow Inquisitor CR 14
• Drow Matron Mother CR 20
• Drow Shadowblade CR 11

I should probably list the drow in the Monster Manual while I'm at it:

• Drow CR 1/4
• Drow Elite Warrior CR 5
• Drow Mage CR 7
• Drow Priestess of Lolth CR 8
• Yochlol CR 10

Waterdeep: Dragon Heist:

• Drow Gunslinger CR 4

Monster Conversions

The internet is a blessing. There are some monsters in this adventure that don't exist in official 5e books. Luckily, there are intrepid souls out there who have made conversions, saving us a lot of time and effort:

• Aranea CR 3
• Bebilith CR 11
  

Concern: I am a bit worried about scaling. Some of these drow are probably too powerful for my group.

The thing about this party, though, is that they use a lot of "encounter-ending" abilities. Asana, the monk has stunning strike, and Linnet, the spellcaster, uses polymorph a lot.

Preserving the Monte Cook-ness

Throughout this conversion, I will suggest throwing out encounters. That said, after reading a bunch of these old Monte Cook adventures, I have learned that there are a number of monsters that he uses over and over. I assume he really likes these monsters, so I will always try to keep them in:

• Hezrou CR 8 (MM pg 60)
• Gray Render CR 12 (Mordenkainen's pg 209)
• Retriever CR 14 (Mordenkainen's pg 222)

It also seems like he is a fan of bodaks (Volo's pg 127) and succubi (MM pg 285).

Drow Research

 

I think before we start this conversion, we should dig through some books and see if there's any 5e drow lore we can use to spice things up. 

I actually wrote a guide to the drow, but that doesn't include stuff from Mordenkainen's Tome of Foes:

• The conflict between Lolth and Corellon led to Lolth taking her elves to the Underdark.
• They believe they are superior to all other creatures.
• Non-drow are slaves, fodder, or sacrifices.
• Lolth sometimes randomly tests her followers by drawing their spirits to the Demonweb. Drow who fail these tests are transformed into a drider.
• Fitness and physical beauty are highly prized in male drow.
• When drow go on raids, they are primarily looking to enslave other creatures.
• Slaves are kept as a sign of status.
• Drow Trance: Unlike surface elves, when drow trance they simply dwell for a time in darkness and silence.

The Demonweb Connection: Drow do not fear demons. Demons are the highest form of slave that a drow house can own.

• Draegloths: The offspring of drow and glabrezu. 
• Yochlols: Personal servants of Lolth, they respond to the will of Lolth alone. All drow assume that some of their friends and neighbors are yochlol in disguise.
• Arachnomancers: Have a supernatural connection to the spiders of the Demonweb Pits.
• Inquisitors: Some can summon a yochlol once per day.
• Shadowblades: These ruthless killers have the power to summon shadow demons.
• Lolth: She demands sacrifices of treasure and blood.
  

Overall Story

Laveth's Plan: 

1. Capture a good cleric for sacrifice.
2. Gather her four power receptacles (hidden throughout a small area of the Demonweb).
3. Over the course of 3 days, perform The Harrowing ritual (which involves killing the good cleric).
4. The ritual will give her power (she will gain 8 levels!), and she will be strong enough to take the Demonweb from her mother.
   

Laveth's Symbol: Only her most trusted allies wear these. The group will need these symbols in order to pass safely through some of the Demonweb.

Adventure Summary

1. Rescue: The heroes try to find a kidnapped elf.
2. Follow Trail: Following a trail of dead birds, the heroes come to a cave.
   
3. Portal: In the caves are the abductors - drow. The abducted elf has been taken through a portal in the cave to the Demonweb to be sacrificed as part of a ritual.
4. Slaads: As the group explore, they see that slaads are attacking the Demonweb (Laveth hired them to provide a distraction while she tries to complete her ritual).
   
5. Stop the Ritual: The group goes through the portal to the Demonweb and try to stop Laveth from completing the ritual. They have 3 days to do so.
   

NPCs

This adventure has a lot of unique villains. Some are loyal to Laveth, others are loyal to Lolth. Those loyal to Lolth could become allies with the adventurers.

Lolth Loyalists

Countess Ullistrin: A vampire that likes to collect corpses and add them to a "party scene" in her home

• Vagdrioth: Consort of the Countess. He is chaotic-minded, and is in charge of administrative information. Has a pet gray render.
  
• Tarestique: 10th level cleric of Lolth, 2nd in command under Countess Ullistrin. 3 large Abyssal Spiders obey her. Keeps 4 elf slaves

Nulise: A blackguard, she is keeping an eye on the yochlol to see if there are traitors in their midst (there are).

• Bloodlust: Her pet raven, has eyes that glow red.

Laveth Loyalists

Laveth: Laveth is the daughter of Lolth, demon queen of spiders. Her father is a male drow wizard. Laveth wants the demonweb for herself.

• Four receptacles store her power.
• She has forged an alliance with slaad mercenaries. She sent them to attack the demonweb.
• Her drow agents have abducted a cleric of Corellon.
• Her symbol: Silhouette of a woman with four spidery appendages.
  

Realthican: Male drow, flesh is scarred in a web-like pattern. His robes have jewels in them set to look like spiders.

Tudrii: A female half-drow/half-demon, Is a rogue/fighter.

Helcav: Male Drow with a spider tattoo on his forehead, wears black and violet robes.

• Oliclin: A bodak that serves Helcav.
  

Eaman: A male arachnomancer who likes to add metal blades to living spiders. Laveth's most powerful servant. 

(Mercenary) Gylgurdreg: A death slaad who works with the slaad mercenaries.

Captives

• Alerian: A cleric of Corellon, god of the elves. Captured, is the key sacrifice in the ritual.
• Brudis Charif: Half-elf fighter, friend of Alerian, also captured.
  

(page 26) A Walk in the Woods

The elves have two problems:

1. There's a lot of dead birds in the woods.
2. Alerian, their high priest of Corellon, has gone missing (he was abducted by teleporting demons while he slept).

Dead Birds: The birds appear to have burst open from the inside. There are no maggots and no scavengers try to eat the remains.

Follow the Trail: The group follows the trail of dead birds, and notice that they encounter more and more strange tiny spiders. These spiders are black and red, and have tiny spikes and hooks on them.

The heroes can deduce that these spiders are poisonous to eat. The birds are dying because they are trying to eat these little planar spiders from the Abyss.

If the group somehow waited TWO DAYS to start investigating, there is a 30% chance per hour that they encounter a drow raiding party.

Medium 5e encounter:
1 Drow (MM pg 128)
1 Drow Mage (MM pg 129)
3 araneas

(page 25) Infested Cabin

The trail of dead birds leads to this cabin. The spiders cover the door.

Inside are two corpses - a human and a half-elf killed by the spider swarm.

Continuing to follow the path of dead birds leads to a ridge, and the aranea caves.

(pg 25) Aranea Caves

Note About Running the Caves: When I run this, my plan is to skip through most of these encounters. I might keep the ambush in A2 because it seems like a really cool encounter, but I'm ditching almost everything else.

I am worried that the group will get bored with what some might perceive to be "filler" fights. We're here for the demonweb, not araneas.

A1. Outside the Caves: Ridge is 80 feet high. There is a large boulder semi-concealing a cave entrance. You can squeeze past the boulder to get into the cave.

A2. Entry Cave: Ceiling is 40 feet high. 6 Araneas are hiding on the ceiling.

6 araneas

• Special attack: +5 to hit, a web strand pulls a character up to the ceiling. On the aranea's next turn, it tries to web them to the ceiling (+5 to hit, restrained.

Trap: There is an illusion (detect: Investigation check DC 12)concealing a trench-like spiked pit.

Let's use the spiked pit from the DMG

• 5d6 bludgeoning damage and 11 (2d10) piercing damage, CON save DC 13 or 22 (4d10) poison damage, half as much on a success.
  

A3. Storage Cave: 25 bundles (blood-drained corpses of elves, deer, and humans).

A4. Shaft Down: This shaft leads 100 feet deep into an underground river. STR check DC 10 or the current pulls you to A5.

A5. Guardians: The river leads to a pool that is 4 feet deep. The current might pull you into an underwater tunnel that drops you down to area A8. STR check DC 10 each round to resist.

There is a northern ledge. On top of it are a drider and 4 araneas.

Medium encounter:

• 1 drider (MM pg 120)
• 4 araneas

Note: This one definitely feels like an unnecessary encounter. My plan is to have the drider be here, but not attack. It hates the drow and if anything, will give the heroes information on what the drow are up to (it speaks Elvish and Undercommon).

Also, Laveth has drider servants in her temple (area d12). This drider might have been offered the opportunity to serve her, but turned it down, and has fled through the portal to escape her wrath.

A6. Tyeeinish's Cave: Dark cave with web-filled niches (spider-lairs).

Tyeenish: The aranea ruler, a half-demon. I made her a re-skinned retriever.

Tyeenish
Large beast, lawful evil

Armor Class 15 (natural armor)
Hit Points 210 (20d10 + 100)
Speed 50 ft., fly 50 ft., climb 40 ft.

STR 22(+6) DEX 16(+3) CON 20(+5) INT 18(+4) WIS 11(+0) CHA 4(-3)

Saving Throws Dex +8, Con +10, Wis +5

Skills Perception +5, Stealth +8

Damage Immunities cold, fire, lightning, poison; bludgeoning, piercing, and slashing from nonmagical weapons that aren't adamantine

Condition Immunities charmed, exhaustion, frightened, poisoned

Senses blindsight 30 ft., darkvision 60 ft., passive Perception 15

Languages understands Abyssal, Elvish, and Undercommon but can't speak

Challenge 14 (11,500 XP)

    Shapechange: Tyeenish can use its action to polymorph into a Medium beast or humanoid creature of CR 2 or lower, or from another form back into its own form. Tyeenish retains its Int, Wis, and Cha scores and its current hit points while polymorphed; otherwise, it takes on all the attributes of the adopted form. It can cast spells if the adopted form can provide the spell’s verbal and somatic components, and it retains its paralytic poison trait if the adopted form has a bite attack. A shapechanged aranea reverts to its natural form when slain.

    Spellcasting: Tyeenish uses Intelligence as their casting ability (DC 16, attack +9) and require no material components for their spells. Typical known spells are listed below, but individual aranea can know different spells.

• Cantrips (at will): dancing lights, mage hand, ray of frost
• 1st level (4 slots): mage armor, magic missile, shield, silent image, ventriloquism
• 2nd level (4 slots): invisibility, mirror image
• 3rd level (3 slots): lightning bolt, 
• 4th level (2 slots): Stoneskin

    Spider Climb: Tyeenish can climb any surface without making ability checks.

Actions

        Bite: Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 6) piercing damage,  and the target must make a successful DC 16 Con saving throw or become poisoned (see Paralytic Poison, below).

        Paralytic Poison: The poisoned creature has tactical disadvantage on attack rolls and ability checks. At the end of each of its turns, the poisoned creature must attempt a Con saving throw. On a result of 16 or higher, the poisoned condition ends and the character becomes immune to this aranea’s poison. On a result of 11–15, the poisoned condition continues. On a result of 10 or lower, the creature becomes paralyzed and no more saving throws are needed. Paralysis lasts for 1 hour or until the poison is neutralized

    Webs (recharge 5, 6): Ranged Weapon Attack: +11 to hit (range 30 ft./60 ft.; one creature). Hit: The target is restrained by webs. A webbed creature can use its action to attempt a DC 16 Str (Athletics) check to escape. The web can also be destroyed by 5 points of slashing or fire damage against AC 10.

Large Abyssal Monstrous Spiders: They are just Giant Spiders (mm pg 328) with resistances: cold/fire.

A7. Web Lair: Floor is 100 feet down. Thick webs criss-cross the area. Things are wrapped in cocoon-like sacks.

• Cave floor is 100 feet down.
• Sacks: Hold 100+ aranea eggs.
• Bottom of Cave: a coffer with 240 gp, 10 gems worth 50 gp each, a jewelled bracelet worth 100 gp, and a potion of clairvoyance (DMG pg 187)

A8. Demons at Rest: Pool, column, water pours through hole in west wall.

Lurking here are the villains who actually abducted Alerian.

• Ilvadidra, Drow Priestess of Lolth CR 8 (MM pg 129), leader of the group.
  
• Ssoril, a hezrou CR 8 (MM pg 60)
• Alysthene, a succubus servant of the hezrou CR 4 (MM pg 285)
• Chazyk, a vrock CR 6 (MM pg 64)

Hard Encounter: As written, this is a deadly encounter. Let's say that the vrock is a coward and flees. That makes this a "hard" encounter, which sounds right to me.

I envision this as a scene where the group can spy on them and listen to their conversation, learning some details about how soon Laveth will rule the Demonweb. They speculate on how they will be rewarded. They should probably say out loud that the ritual will be done in three days, so tha tthe group is aware that they are on a time limit.

Symbol of Laveth: Ilvadidra has a symbol of Laveth -  a silhouette of a woman with 4 spidery appendages coming out of her sides.

A9. Another Web Lair: Webs, columns.

Hidden in the webs are two spider-silk bags.

• Bag 1: 12 gems, 50 gp each. 200 gp, 780 sp. Potion of Greater Healing (heals 4d4+4), and a potion of hill giant strength (DMG pg 187).
• Bag 2: 260 gp, 600 sp, potion of resistance (poison) (DMG pg 188).
  

A10. The Gate: The portal is a "hole in space" that "leads into a starry, black void."

Those who pass through appear in D1. The gate can only be damaged by Laveth's 4 power receptacles.

Bebilith: A bebilith is guarding the gate. The bebilith is CR 11, which is an easy encounter for a 12th level group. I probably wouldn't use this encounter anyway, so no big deal.

A11. Drow Garrison: In the adventure, there are 7 male drow and 2 spellcasting drow here. That actually scales nicely! It's a hard encounter.

• 7 Drow (MM pg 128)
• 2 Drow Mages (MM pg 129)

Treasure: 2 iron boxes (locked and trapped)
Lock: DC 20
Trap: (Spot trap = Investigation DC 20, disable = DEX check w/ tools DC 15) Poison needle. Take 1 piercing dmg and 11 (2d10) poison dmg, and roll a CON save DC 15. Fail = poisoned for 1 hour.

• Potion of greater healing (DMG pg 187)
• Scroll of spider climb (PH pg 277)
• Scroll of greater restoration (PH pg 246)
• Scroll of remove curse (PH pg 271)
• scroll of heal (PH pg 250)
• Scroll of fly (PH pg 243)
• Scroll of see invisiblity (PH pg 274)
• Scroll of Summon Lesser Demons (Xanathar's pg 167)

I think that, for my game, I'll just leave this room empty, too.

(pg 30) Demonweb (Areas D1 - D19)

Let's mix in the info on the Demonweb from the DMG:

"Lolth’s layer is an immense network of thick, magical webbing that forms passageways and cocoon-like chambers. Throughout the web, buildings, structures, ships, and other objects hang as if caught in a spider’s snare. The nature of Lolth’s web creates random portals throughout the plane, drawing such objects in from demiplanes and Material Plane worlds that figure into the schemes of the Spider Queen. Lolth’s servants also build dungeons amid the webbing, trapping and hunting Lolth’s hated enemies within crisscrossing corridors of web-mortared stone.

Far beneath these dungeons lie the bottomless Demonweb Pits where the Spider Queen dwells. There, Lolth is surrounded by her handmaidens — yochlol demons created to serve her and which outrank mightier demons while in the Spider Queen’s realm."

In this adventure, it says: "Below the Demonweb, in chasms sunken within absolute darkness, lie the dreaded Demonweb Pits."

Stages: In many of these encounters, we are given information on what creatures are in the area depending on what "stage" of the ritual is occurring. The group gets two longs rests... if they take a third, the ritual gets completed and Laveth succeeds in her evil scheme.

In the early stages, the slaads are fighting the drow. In stage 3, the conflict has been decided one way or another.

Power Receptacles: The group is going to need to find the four power receptacles to defeat Laveth. These things are hard to find. Here they are:

1. D9D. Balcony: Hidden inside a hollow statue.
2. D14C. The Captain: Embedded in the remains of the captain on the pirate ship.
   
3. D18C. Laveth's Chamber: In a hidden compartment in the floor.
   
4. P4. The Ritual Chamber: Resting on the altar.
   

My Campaign: I'm handing out the 20 sigils needed for the Labyrinth of Madness in these adventures, so I am thinking that I'll put one sigil on each of the power receptacles? Or maybe, I'll have a sigil near each  receptacle? So the sigil is subtly guiding the group to their objectives?

Symbols of Laveth: If the group aren't wearing symbols of Laveth, they can't access the final areas. I will be sure to note which areas contain symbols.

Demonweb: The magic of the web creates magic, random portals that draws in buildings, structures, and ships.

• Doors: Unlocked, wooden doors.
• Ceilings: 15 feet high.
• Magic Conditions: Web spells spread out to fill twice the area they normally should.
• Saves vs. poison are at disadvantage.
• Spider climb lasts twice as long.

Pathways: Round tubes made of extra-tough webbing.

• Immune to fire/cold/lightning.
• Has a damage threshold of 10, has 20 hit points.
• The area outside the map is a black void filled with strands of webbing in all directions. 
• Falling: Plunge 10d100 feet before hitting a web strand and becoming caught. Take falling damage as normal.
  

D1. Arrival: The heroes pass through the gate. Web walls, ceilings and floor show faces of the souls of the damned.

Wall: Damage Threshold 20, HP 200. If broken, 10 chaos specters are released from the interior walls and attack anyone nearby.

10 Chaos Specters: They are normal specters with chaotic alignments. (MM pg 279)

D2. Nexus: Dead slaads. 

• Stage 2 & 3: corpses are gone.
  

D3A. Drow Defenders:

1. Stage 1: 4 drow (MM pg 128) vs 3 green slaad (MM pg 277), 2 blue slaad (MM pg 276)
   
2. Stage 2: 5 drow vs 1 red slaad captive (MM pg 276)
   
3. Stage 3: 5 drow

Treasure: 5 trunks: 2d6 gems worth 50 gp each

Spellbook: Cover is cornugon hide, pages made of dried webbing.

D3B. Room in Disarray: Weapons, mats. 

Trap: The door to 3c is trapped.

D3C. Priestess's Chamber: Bed suspended by chains, Paintings, Stone, 3 spiders, 4 shackled elves

Door Trap: Glyph of Warding 20 foot radius thunder damage DEX save DC 15 5d8 thunder damage, half on save.

Note: Tarestique is loyal to Lolth and serves the vampire Ullistrin.

Tarestique and the 3 spiders are a medium encounter

• Tarestique: Drow Priestess (MM pg 129)
  
• 3 Large Abyssal Monstrous Spiders: They are Giant Spiders (mm pg 328) with resistances: cold/fire.

Treasure: (cursed) Onyx statue of Lolth (1,000 gp): Curse: When taking a rest, gain no benefits. Remove curse (PH pg 271) ends this effect. Drow are immune to this curse.

Wardrobe: Clothing, perfumes, spyglass, whip, manacles, 3 potions of greater healing (heal 4d4+4), scroll of raise dead, bag with 100 gems worth 10 gp each, coin purse containing 50 pp.

D4. Demon Roost: Bronze trap door. Pull open: Room with a pool and perches. 

(4 vrocks and a hezrou are way too hard. 1 vrock and a hezrou are a medium encounter)

• 1 Vrock (MM pg 64)
  
• 1 Hezrou (MM pg 60)
  

Treasure: 10, 543 cp, 5,390 sp, ring of resistance (lightning) (DMG pg 192).

D5. Countess Ullistrin's Chambers: Keep in mind that Ullistrin is loyal to Lolth, and will help the group if given the opportunity. 

• Finding Ullistrin: The group will likely encounter Ullistrin in area D6C., but they might find her resting in her sarcophagus in D5B.
  
• Potential Ally: She can tell the group that Laveth has a power receptacle hidden in D18C. Laveth's Chamber.

D5A. The Endless Gate: Corpses of humanoids (completely drained of blood) are posed as if they are at a party. 2 invisible gray slaads prowl about. 

(2 gray slaads are a hard encounter)

• 2 Gray Slaads (MM pg 277)

Notes: I'm very worried about this being an unnecessary combat, so I might have the drow atack the slaad no matter what, to show the group that these drow not only hate the slaad, but they are clearly wearing symbols of Lolth.

Treasure: 54 pp, gold ring with ruby (120 gp), silver/gold statuette  (300 gp),

• Stage 2: 2 gray slaads (MM pg 277) are fighting 6 drow (MM pg 128)
  
• Stage 3: 6 drow (MM pg 128)
  

D5B. Countess Ullistrin's Resting Place: Stone sarcophagus.

Secret Compartment in the Sarcophagus: Trap: 30 ft square poison gas: CON sv DC 15 or 3d12 poison damage, save for half.

Treasure: 300 gp, jeweled scepter (1,000 gp), crystal ball (DMG pg 159).

• Stage 1: Nobody's here.
  
• Stage 2: Countess is in the sarcophagus.
• Stage 3: Nobody's here.
  

D6A. Outer Chamber: 8 floating discs, bronze statue of drow on each.

• 2 discs: have no statues
• Bronze-topped Wood Desk with papers and files.
• Cushions

D6B. Trapped Hall: Walls and floors, spider-like frescoes.

Step in from D6A. (Trap): The first person to step on the floor triggers symbol of death that affects only them.

• Detect: Investigation Check DC 15
• Disable: Arcana or DEX check with thieves' tools DC 15.
• Trigger: Touch the door to D6C.
  
• Effect: CON save DC 15, 10d10 necrotic damage, half on save.

Door to D6C.(Trap):

• Detect: Investigation Check DC 15
• Disable: Arcana or DEX check with thieves' tools DC 15.
• Trigger: Touch the door to D6C.
  
• Effect: Entire hallway filled with a firestorm: DEX save DC 15, 8d6 fire damage, save for half.

D6C. Render's Den: 2 pedestals.

Pedestals: 3 feet wide, 2 feet high. If a battle breaks out, Ullistrin and Vagdrioth each stand on one.

(If all 3 creatures are in here, this is a beyond-deadly encounter. Vagdrioth and the render are a hard encounter alone. The vampire on her own is a medium difficulty encounter!)

• Ullistrin, Vampire (MM pg 279)
  
• Vagdrioth, drow mage (MM pg 129)
  
• Gray Render (Mordenkainen's page 209)
  

D7. Yurganthaor's Lair:

by Stephen Daniele

Globe: AC 18 Damage Threshold 20 HP 150

• 15 foot diameter black sphere hovering 10 feet off the floor. 
• Place for the nalfeshnee to sleep among his pile of treasure.
  
• If the nalfeshnee dies, it vanishes.

The nalfeshnee has the ability to teleport as an action. So, it can teleport in and out of the globe as it likes.

Hole in Floor: Passage to D18A.

(the nalfeshnee is a medium encounter)

• Yurganthaor, Nalfeshnee (MM pg 62)
  

Treasure: 1,320 gp, four 50 gp gems, scrolls of wall of fire (PH pg 285) and telekinesis (PH pg 280).

D8. Upper Chamber: A trap door in the ceiling leads into a little supply room. Empty crates, barrels, and sacks. Good place to rest!

• Stage 1: Room is empty
• Stage 2: 2 blue slaads (MM pg 276) (2 slaads is a medium encounter)
  
• Stage 3: Room is empty

D9. Crystal Tower of the Yochlol: 100 ft tall tower made of purple crystal. The yochlol here are loyal to Lolth.

Notes: I am very amused at the idea of the heroes meeting with the yochlol and hanging out with them in a sunken pit of gunk in D9C., explaining Laveth's plot and asking for help.

From what I can tell from the text, these yochlols are not loyal to Lolth? I mean, they have one of Laveth's power receptacles stashed in a statue, so yeah they must be. Nulise, a drow blackguard, has been sent by Lolth to check them out. 

This will get weird if the yochlols use detect thoughts on the heroes. The yochlols are very powerful! The group could be in big trouble. Nulise could bail them out, I guess.

Honestly I'm sort of inclined to change this. Maybe one yochlol is a traitor? And that traitor can be rooted out?

by Stephen Daniele

Yochlol Research 

I'm going to dig through the Monster Manual real quick to see what we can learn about yochlols:

• Handmaidens of Lolth
• Lolth's spies, taskmasters, and agents. Serve no demon lords except Lolth.
• Shape Shift: "Outside the Abyss, a yochlol can assume the guise of a female drow or monstrous spider to conceal its demonic form."
• True Form: A pillar of yellow slime with a single eye.
• Poison Touch: Touch is venomous.
• Spells: Can cast detect thoughts, web, and (1/day) dominate person.
• Mist Form: Can become a poisonous cloud with flying speed of 30.
  

D9A. Defenses: (Trap) 5 dragon heads on the floor.

• Disable: Speak password, or cast Dispel Magic (PH pg 234) Make an ability check using your spellcasting ability DC 15, or destroy heads (see stats below).
  
• Trigger: If you enter the tower without speaking the password, the dragon heads all breathe 5-foot wide streams, 1 head per character, per round.

Dragon Head: AC 14 Damage Threshold 10 HP 50 

1. Red: DEX save DC 12 10d6 fire damage, half on save.
2. Black: DEX save DC 12 8d6 acid damage half on save.
3. White: DEX save DC 12 7d6 cold damage, half on save
4. Blue: DEX save DC 12 9d6 lightning damage, half on save.
5. Green: DEX save DC 12 8d6 poison damage, half on save.

D9B. Guard Chamber: "Drow matron in spider silk robes" (a yochlol with 2 yochlol nearby in mist form).

• Detect Thoughts: I am thinking that the yochlol can use detect thoughts to scan a character's mind and will immediately understand why the heroes are here. She could press further, giving the character a WIS save DC 14 to block it. 

Bas-reliefs: Spiders menacing victims caught in giant web.

(2 yochlols is a hard encounter. 3 is deadly!)

• 3 yochlols (MM pg 65)
  

D9C. Yochlol Lair: (each lair is home to 3 yochlol)

3 Sunken Pits: Give off a pungent odor. Yochlols are in the pools, giggling.

• Getting in a Pit: Make a CON save DC 11. Fail: Catch sewer plague. Symptoms manifest in 1d4 days.
  

Treasure: Small steel boxes (Trap: Glyph of warding. Detect: Investigation check DC 15. Disable DC 15. Effect: 20 foot radius DEX save DC 15 5d8 fire damage, half on save)

• 2 gems worth 50 gp, 20 pp, small silver brooch of a spider (this grants access to restricted areas)

D9D. Balcony: Drow woman with two-bladed sword on balcony, has a large black raven with black eyes.

• Nulise: Blackguard (Volo's pg 211)

Notes: As a CR 8, she is not a threat to the party. But this place isn't really about combat - it' about rooting out who is loyal to Laveth, and finding the power receptacle!

For my campaign, which involves the sigils from the Labyrinth of Madness, I might say Nulise has the second sigil on her hand - a clue that she's not the enemy. Maybe I'll put a sigil near each of the power receptacles. Maybe one will be on Alerian.

D9E. Obsidian Queens: 10 obsidian statues depicting female drow.

Statue in Center of Room: (hollow - has a secret latch, splits the statue to reveal the treasure)

• Treasure: Floating inside the statue is one of the power receptacles. Oblong, faceted green gem worth 5,000 gp

D9F. Shrine of Lolth: Statue of Lolth in her half-spider form. Bowl and a knife nearby.

Animated Statue of Lolth: 10 feet tall, 12 feet wide, painted, (...lunges menacingly at those who peer through the door." Has ruby eyes, each worth 500 gp.

East Brazier: Contains a block of incense: If burned, the statue poses regally and expects a blood sacrifice. If a sacrifice is made, bless spell lasts 24 hours.

Fail to burn incense within 5 rounds or remove an eye: The statue screams. All in the room make a CON sv DC 15 10d8 thunder, save for half.

Notes: There was a curse in the 3e version of this adventure, but I'm going to ignore it. I'll just use the "scream" effect.

D10. Nightmare Assassin: Flat platform of rusty iron, dead slaad.

(The CR 14 retriever is a medium encounter)

• Retriever (Mordenkainen's page 222)

Over the Edge: Remember, this is on an open platform. A character could fall off the side and into the nothingness.

• Paralyze: The retriever has a paralyzing beam: "If the paralyzed creature is Medium or smaller, the retriever can pick it up as part of the retriever’s move and walk or climb with it at full speed." 
• Pick Up & Drop: So, it could paralyze a creature, pick it up, move, let go.
  
• Falling: Plunge 10d100 feet before hitting a web strand and becoming caught. Take falling damage as normal.

Dead Slaad Treasure: Potion of Invisiblity (DMG pg 188)

D11. Arachnomancer and Rogue: Beds, dishes

• Stage 1: Realthican and Tudriiare here.
  
• Stage 2: Realthican and Tudriiare here.
  
• Stage 3: Nobody's here (Realthican and Tudrii are at the ritual).
  

(These two are a hard encounter)

• Realthican, Drow Arachnomancer (Mordenkainen's pg 182)
  
• Tudrii, "half-drow/half-demon" (cambion, MM pg 36)

Run? Looking at Realthican's spells, it seems like a good bet is to drop an insect plague and then dimension door away. He doesn't have a lot of bombs to drop. 

Symbol of Laveth: Both Tudrii and Realthican have symbols of Laveth -  a silhouette of a woman with 4 spidery appendages coming out of her sides.

Treasure: 2 locked trunks (Open DC 20, 20 pp, four 100 gp gems, jeweled mirror, 3 potions of greater healing (4d4+4), 1 potion of flying (DMG pg 187).

D11B. Open Platform: Suspended wood platform (descends to D12)

D12. Temple of Laveth: Only servants of Laveth and those bearing her secret symbol are allowed. If intruders enter, 2 driders magically appear in the pool and attack.

Anti-Magic Field: Except in the pool.

Pillars: Web patter, leering demonic face at the top.

Mural: Drow woman holding green gem (Laveth holding power receptacle)

Pool: Shallow, 20 feet across, transparent liquid. 1 foot drop. Radiates enchantment magic.

• Touch Water: CON save DC 15 or stunned for one round. WIS save DC 12 or Laveth controls you. She scars your mind until you save.

(Normally 2 driders is an easy encounter, but the anti-magic field and the pool I think will make up for it)

• 2 driders (MM pg 120)
  

D13A. Helcav and Friend: Walls have sculptures of humanoids riding dragons, fighting demons.

• Stage 1: Helcav and Oliclin.
  
• Stage 2: Drow with spider tattoo on forehead.
• Stage 3: Oliclin is here, Helcav is at ritual.

It's an easy encounter with just the bodak and the mage, so I added some abyssal spiders to bump it up to a medium encounter.

• Helcav, Drow Mage: (MM pg 129) He has a wand of viscid globs.
  
• Oliclin, Bodak: (Volo's pg 127)
• 3 Large Abyssal Monstrous Spiders: They are just Giant Spiders (mm pg 328) with resistances: cold/fire.

Symbol of Laveth: Helcav has a symbol of Laveth -  a silhouette of a woman with 4 spidery appendages coming out of her sides.

D13B. Helcav's Bedchamber: Bed, tables.

Large Bound Chest: (locked DC 20 to open) Mummified drow hand (a hand of the mage), 10 ivory figurines worth 100 gp each, figurines of spider-faced women doing ballet.

• Hand of the Mage: This mummified elf hand hangs by a golden chain necklace. It allows the wearer to utilize the cantrip mage hand at will.

D14. The Ship: Large ship, gray sails.

D14A. Rummaging Fiends: 2 hezrou rummaging for food. 

(2 hezrou is a medium encounter)

• 2 hezrou (MM pg 60) 

Note: While this seems like a superfluous encounter, I do want to make sure the hezrous are present, because they are a Monte Cook favorite and we are running a Monte Cook campaign.

D14B. Doomed Crew: Wrecked ship, ghostly crew materializes.

(easy encounter, I'll probably skip this one).

• 8 chaos spectres (specters, MM pg 279)
  

D14C. The Captain: Foul odor, creature with legs molded to the floor - green object in center of body.

Notes: Let's base the Captain's stats on a mummy lord, which is a CR 15 monster - a hard encounter. We'll use the numbers but swap in powers from the adventure. 

This is a weird monster. It doesn't have a melee attack! It has a 0 speed! In the 3e adventure, it has a bunch of spells, but most of them seemed useless, and I figure that the legendary actions make up for it.

One thing I'm a little unsure of is the breath weapon damage. It's a CR 15 monster, so I just lifted the numbers from the adult bronze dragon... but 101, 88 points of damage seems like a lot.

The point of this encounter is just to get in there, grab the gem, and get out.

The Captain 

Medium undead, Chaotic evil

• Armor Class 17 (natural armor)
• Hit Points 97 (13d8 + 39)  (If this seems low, you could go with 143 HP max)
  
• Speed 0 ft. (yes, zero feet)
  

STR 18(+4) DEX 10(+0) CON 17(+3) INT 11(+0) WIS 18(+4) CHA 16(+3)

• Saving Throws Con +8, Int +5, Wis +9, Cha +8
• Skills History +5, Religion +5 
• Damage Resistances: cold, fire, acid
• Damage Immunities: lightning, necrotic, poison; bludgeoning, piercing, and slashing from nonmagical attacks
• Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
• Senses darkvision 60 ft., passive Perception 14
• Languages Common, Abyssal
  

Challenge 15 (13,000 XP)

Magic Resistance. The captain has advantage on saving throws against spells and other magical effects.

Death Gaze: When a creature that can see the captain’s eyes starts its turn within 30 feet of the captain, the captain can force it to make a DC 16 Constitution saving throw if the captain isn’t incapacitated and can see the creature. If the saving throw fails by 5 or more, the creature is reduced to 0 hit points, unless it is immune to the frightened condition. Otherwise, a creature takes 16 (3d10) psychic damage on a failed save.

Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it has disadvantage on attack rolls against the captain until the start of its next turn. If the creature looks at the bodak in the meantime, it must immediately make the saving throw. 

Actions

Dreadful Glare. The captain targets one creature it can see within 60 feet of it. If the target can see the captain, it must succeed on a DC 16 Wisdom saving throw against this magic or become frightened until the end of the captain’s next turn. If the target fails the saving throw by 5 or more, it is also paralyzed for the same duration. A target that succeeds on the saving throw is immune to the Dreadful Glare of the captain for the next 24 hours.

Breath Weapon (Recharge 5–6). The captain exhales force energy in a 30-foot cone. Each creature in that area must succeed on a DC 16 Dexterity saving throw, taking 88 (16d10) force damage on a failed save, or half as much damage on a successful one.

Legendary Actions

The captain can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The captain regains spent legendary actions at the start of its turn.

• Blinding Glare. The green power receptacle flares with sickening light. Each creature within 5 feet of the captain must succeed on a DC 16 Constitution saving throw or be blinded until the end of the creature’s next turn.
• Abyssal Word (Costs 2 Actions). The mummy lord utters an Abyssal word. Each non-undead creature within 10 feet of the captain that can hear the magical utterance must succeed on a DC 16 Constitution saving throw or be stunned until the end of the captain’s next turn.
• Channel Negative Energy (Costs 2 Actions). The captain magically unleashes negative energy. Creatures within 60 feet of the captain, including ones behind barriers and around corners, can’t regain hit points until the end of the mummy lord’s next turn.

Treasure: Power Receptacle: Green gem worth 5,000 gp.

D15. Material World Gate: 10 foot platform with runes, swirling column of violet mist.

Column of Mist: Gate to a prime world the Lolth conquered long ago, and has grown bored with. It's a wasteland, with ruined cities overrun by demons, monstrous spiders, and undead. 

• The world is dark and cold, sun is shrunken and white. Ruined cities, withered plants, undead.
• The portal/gate brings you to the bottom of a crater.
• Crater is guarded by an iron golem (MM pg 170) in the shape of a spider. 

(One iron golem is a hard encounter!)

D16. Dimensional Interference: How cool is this? We're about to learn how Lolth pulls things into the Demonweb!

D16A. Abyssal Clock:There's a pit.. and a clock.. see the pic. A pit with 12 numerals around it, lever points at 4.

by Stephen Daniele

Clock: Shaft slowly points to hour.

Pit: Permanent darkness (PH pg 230) spell. 30 feet deep, 10 feet of acid (damage: 10d10 acid). Has 3 tentacles!

Disturb the Clock: 3 large, metal tentacles grapple and try to pull you into the pit. Up to 3 medium creatures at once, or 1 large creature.

Notes: There is actually a similar scenario in the Acquisitions Inc. book that we can draw inspiration from here. The enormous tentacles use the stat block of a giant constrictor snake with these changes:

    It can reach anywhere inside this room.
    It has no bite attack.

Metal Tentacles

AC 12 HP 60 (8d12 + 8) Speed 30 ft., swim 30 ft.
STR 19(+4) DEX 14(+2) CON 12(+1) INT 1(−5) WIS 10(+0) CHA 3(−4)

Skills Perception +2
Senses blindsight 10 ft., passive Perception 12
Languages —
Challenge 2 (450 XP)

Damage Immunities: acid

Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned

Actions

Constrict. Melee Weapon Attack: +8 to hit, reach: this room., one creature. Hit: 13 (2d8 + 4) bludgeoning damage, and the target is grappled (escape DC 16). Until this grapple ends, the creature is restrained, and the tentacle can’t constrict another target.

A creature grappled by the tentacle is pulled to the edge of the pit. On the next round, if the creature is still grappled, the tentacle pulls it into the acid pit, taking 10d10 acid damage. There, the tentacle has three-quarters cover, and the creature can’t breathe.

D16B. Open Area: 4 obelisks with knobs. Large Iron lever. Floating image of a desert with red sand.

4 Obelisks: Each has a large round knob

• Generates the floating image
• Knobs can be turned like dials, bring different worlds/places into view.
• Only Lolth can use this device accurately. Too difficult to pinpoint a specific person or place.
  

Large Round Lever: Has 12 notches/settings

• Numbers correspond with the numbers on the clock in D16A.
• When the lever is placed at a given position at the clock reaches that hour, whatever is shown in the image is pulled into the Demonweb.
• There is no control over where in the Demonweb the captured mass appears.

Hazy Image: Floating in the middle of the room hazy image of a desert of red sand.

• Scene from a random world in the multiverse. Obelisks control what world is shown.
  

D16C. Vil the Marilith: Bed, draperies.

Marilith (MM pg 61)

Her swords:

• Shivatri +1 scimitar
• Kalivos: +1 scimitar
• Dedrafensor +1 longsword
• Tyranny +1 longsword
• Zhul +1 battleaxe
• (I don't know why she has only 5 magic weapons)
  

Treasure: 3 golden armbands (50 gp each), gold tiara (250gp), 12 gold bars (300 gp total), coffer containing 250 pp, shield of missile attraction (DMG pg 200).

D17. Barracks: Stone building.

D17A. Terrible Remains: 23 dead drow. 2 dead succubi (all killed by slaad).

Treasure: 33 gp, 89 sp, silver mirror worth 50 gp.

D17B. Large Closet: (Door is locked, open DC 20) Swords, shields, mithral chain.

• 20 doses of drow poison
• 3 doses of wyvern poison

D17C. Slain Demon: Dead vrock.

D17D. Death on Two Legs: The death slaad who apparently killed all of these drow is here.

Gylgurdreg, death slaad (MM pg 278)

Traitor: Just want to point out that it can shapechange! It could pretend to be a drow, covered in blood. Maybe it even joins the group. then turns against them at an opportune time, using cloudkill, fireball, and invisibility to devastating effect.

(Note: a death slaad is an easy encounter for a lvl 12 group.)

Treasure: 23 pp, 140 gp, jeweled comb (200 gp)

Laveth's Palace: Tall, gothic, doors unlocked.

D18A. Grand Hall: Chandeliers hang from ceiling. Guarded by Laveth's gargantuan spider.

Gargantuan Abyssal Spider

Gargantuan beast, unaligned

• Armor Class 14 (natural armor)
• Hit Points 310 (20d20 + 100)
• Speed 40 ft., climb 40 ft.

STR 22(+6) DEX 16(+3) CON 20(+5) INT 3(−4) WIS 11(+0) CHA 4(−3)

• Saving Throws Dex +8, Con +10, Wis +5
• Skills Perception +5, Stealth +8
• Damage Immunities cold, fire, poison; bludgeoning, piercing, and slashing from nonmagical weapons that aren't adamantine
• Condition Immunities charmed, exhaustion, frightened, paralyzed, poisoned
• Senses blindsight 30 ft., darkvision 60 ft., passive Perception 15
  

Languages understands Abyssal, Elvish, and Undercommon but can't speak

Challenge 14 (11,500 XP)

• Spider Climb. The spider can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
• Web Sense. While in contact with a web, the spider knows the exact location of any other creature in contact with the same web.
• Web Walker. The spider ignores movement restrictions caused by webbing.
  

Actions

Multiattack. The spider makes two foreleg attacks and uses its force or paralyzing beam once, if available.

Foreleg. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 15 (2d8 + 6) slashing damage.

Web (Recharge 5–6). Ranged Weapon Attack: +11 to hit, range 30/60 ft., one creature. Hit: The target is restrained by webbing. As an action, the restrained target can make a DC 15 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 10; hp 5; vulnerability to fire damage; immunity to bludgeoning, poison, and psychic damage).

D18B. Laveth's Right Hand Man: Bedroom, Alchemy stuff, spider parts.

Alchemy: Looks like he is adding metal parts to spiders.

(The arachnomancer is CR 13, a medium encounter).

Eaman, drow arachnomancer (Mordenkainen's pg 182)

Top Shelf of Wardrobe: ornate silver box (worth 100 gp) filled with 230 pp

Symbol of Laveth: Eaman has a symbol of Laveth -  a silhouette of a woman with 4 spidery appendages coming out of her sides.

Treasure: Web Armor

• Web Armor: Comes in a large flask. Action: Coat body +7 AC (Does not impose Disadvantage on Dexterity (Stealth) checks or have a Strength requirement)., lasts 24 hours and then dissolves (probably dissolves in sunlight after 1 hour).
  

D18C. Laveth's Chamber: Pillow Floor, dead elf hung from chains, (hidden compartment in floor has receptacle).

Dead Elf: Laveth drank his blood.

• Stage 1: Laveth is here.
• Stage 2: Laveth is in D18E
• Stage 3: Laveth is in the ritual chamber.

Stats: I'll put Laveth's stats down in the ritual chamber.

Treasure: In a hidden compartment in the floor is a Power Receptacle (green gem worth 5,000 gp).

D18D. Gas Trap: Walls carved with faces in torment. 4 gold censers hung from ceiling (censers are 20 feet up).

• Trigger: Cross the room without bearing a symbol of Laveth
• Effect: Both doors seal with arcane lock (PH pg 215). poison gas billows from the 4 censers. CON save DC 15 10 poison damage per round.
• Disable Poison: Plug holes in 4 censers takes 4 actions, sleight of hand DC 12.

D18E. The Spider Throne: Ebony throne with two extremely valuable rubies. has eight twitching spider legs.

Throne (Trap): If you sit on the throne or mess with the rubies on it, all 8 legs cast finger of death on the offending creature! CON save DC 15 7d8+30 necrotic damage, half on save.

• Stage 1: 2 Abyssal Spider Ghosts
• Stage 2: Laveth on the throne (her stats are in the ritual chamber section below. She can use the throne's attacks!)
  
• Stage 3: 2 Abyssal Spider Ghosts

(2 spiders is a super-easy fight, but this room isn't about the monsters. It's about the throne, which is 100% an instant death trap).

Finger of Death: Remember that a humanoid killed by finger of death rises at the start of Laveth's next turn as a zombie that is permanently under her command, following her verbal orders to the best of its ability.

2 Abyssal Spider Ghosts: We can just use phase spider stats (MM pg 334).

Treasure: The 2 rubies are worth 10,000 gp each.

S19. Orifice: Purple light, hole with smoke, strand of web from ceiling drops 1,000 feet down into pit.

This strand lands into a Demonweb Pit (P1. Laveth's Secret Garden)

• Stage 1: Nobody here.
  
• Stage 2: Nobody here.
  
• Stage 3: Any villains that the group hasn't encountered yet (Realthican, Tudrii, Helcav [with Oliclin], and Eaman).
  

Demonweb Pits

These pits collect anything that falls from the demonweb. The sides of the pits are made from semi-solid, impenetrable darkness. You can fly from one pit to another.

P1. Laveth's Secret Garden: Round platform covered in plants (Iron hatch hidden in the ground). Green/yellow bell flowers.

24 Bell-Flower Blooms: If you are not wearing a Laveth symbol, d4 flowers attack each round.

AC 10 HP 10
Damage Immunities: acid
Damage Vulnerabilities: fire, cold

Actions

Melf's acid arrow (PH pg 259): rg 90 +8 to hit. On a hit, the target takes 4d4 acid damage immediately and 2d4 acid damage at the end of its next turn. On a miss, the arrow splashes the target with acid for half as much of the initial damage and no damage at the end of its next turn.

Iron Hatch: (Locked DC 20) iron ladder.

P2. Norded's Head: Iron ladder 30 ft square room, 20 feet below. 2 barrels, dwarf's head floating. It speaks.

Dwarf Head: Surrounded by a wall of force (PH pg 285). Thunder passes through it.

Nordred's attacks pass through the wall of force. Let's say he can cast a modified version of destructive wave (PH pg 231) at will: Each creature you choose within 30 feet of you must succeed on a Constitution saving throw DC 15 or take 10d6 thunder damage, and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone.

• If wall of force is destroyed, it restores itself in d4 rounds.
• Nordred is churlish. People without a symbol of Laveth can't pass.
• If the group can get past the wall of force, Nordred is easily defeated. I mean, he's just a head.
  

Metal Plate: Behind head, bears symbol of Laveth. The plate is not in the wall of force.

• Touch the plate: Teleported to P3 in a flash of light.

P3. The Prison: Platform suspended by webs. Center cut out. 7 globes, each holding a creature, are floating above the pit.

Plates: One sends you back to P2, the other sends you to P4.

Spheres: Permanent Otiluke's resilient sphere (PH pg 264) Nothing passes through (can breathe, though). The sphere is immune to damage.

• Disintegrate (PH pg 233) spell destroys a sphere without harming the creature inside. 

Release: Creature will fall into pit, 1,000 feet down. A retriever (Mordenkainen's pg 222) lurking down there will then kill the creature.

1. Globe 1: Tzarrc: A vrock (MM pg 64) that angered Laveth. Dimensional shackles on legs.
2. Globe 2: Ghaundan: A drider (MM pg 120) that betrayed Laveth.
3. Globe 3: Maldorl: Drow (MM pg 128)who tried to spy on Laveth for Lolth.
4. Globe 4: Esad: Male elf (commoner MM pg 344), sacrifice.
5. Globe 5: Nariel: Female elf (commoner MM pg 344).
6. Globe 6: Alerian: Elf cleric of Corellon (priest MM pg 348), the person the group is looking for. (If in stage 3, Alerian's bubble is empty).
   
7. Globe 7: Brudis Charif: Half-elf fighter (thug MM pg 350), ally of Alerian.

Treasure in Pit: 230 sp, 60 gp.

P4. The Ritual Chamber:

by Stephen Daniele

(Note: If you're in Stage 3, any receptacles that the group didn't obtain are now here by the altar)

• The heroes appear on a stone ledge.
• The ledge overlooks a large chamber filled with huge webs.
• In the webs, suspended 20 feet above the heroes, is a rusted iron platform
• On the iron platform is an altar. 
• Floating above the altar is the final power receptacle.
  
• Reaching the platform: Flying and teleporting.
• Scarlet mist rises from below.

Scarlet Mist: (drow immune). CON save DC 12. Fail: Become incapacitated, Fall into a deep sleep filled with horrible nightmares. Holding your breath gives you advantage on the save.

Ledge: Lined with four horizontal rows of 13 crystalline spiders (52 total). Each embedded in the wall.

1. Row 1: Flush with the floor.
2. Row 2: 10 feet above the floor.
3. Row 3: 30 feet above the floor.
4. Row 4: 50 feet above the floor.

(Trap) Crystalline Spiders: AC 10 HP 5 (Anyone holding a power receptacle is immune to this trap.)

• Invisible rays connect one spider to another, forming a lattice. 
• Detect: Those who can see invisible can see the rays. 
• Disable: Shattering the spiders shuts down the trap.
• Deactivate: Say in Drow: "All hail Laveth!"
  
• Avoid Rays: Acrobatics check DC 15 to move through without passing through a ray.
• Pass Through a Ray: Every 5 feet of movement, make a CON save DC 15 or take 4d10 force damage.
  

Who is here?

1. Stage 1: Empty
2. Stage 2: Empty.
3. Stage 3:

Laveth stands atop the altar, her demonsblood sword drawn. Alerian is lying on the altar, overcome by the scarlet mist.

1. She must kill him and allow his blood to spill on the altar.
2. Then she must touch each of the receptacles to the altar. 
3. As she touches them, each receptacle turns to powder, and Laveth is infused with green energy.

Laveth is an arachnomancer (Mordenkainen's page 182) with a few changes. 

• AC: She's wearing web armor, which gives her an AC of 20.
• HP: She has max HP: 250
• Damage Immunities cold, fire, lightning, poison; bludgeoning, piercing, and slashing from nonmagical weapons that aren't adamantine 
• Condition Immunities charmed, exhaustion, frightened, poisoned
• Immutable Form: Laveth is immune to any spell or effect that would alter her form.
  
• (Melee Attack) Demonsblood Sword: +10 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) slashing damage, plus 21 (6d6) poison damage.
  

Demonsblood Sword: +3 longsword, made of hardened demon's blood.

For the sake of simplicity, let's say that this blade is made from the blood of a yochlol. That gives the blade the yochlol's melee attack effect: longsword damage +3,  plus 21 (6d6) poison damage.

Running the Final Battle: Running just Laveth against the group might be too easy. But if the retriever (Mordenkainen's pg 222) from the pit in P3. joins in, now we have a deadly final battle!

If the Ritual is Completed: Laveth now has the stats of a drow matron mother (Mordenkainen's pg 186)

Concluding the Adventure

If Laveth fails to complete the ritual: Her mother re-takes this portion of the Demonweb, killing her underlinds. Laveth is imprisoned in Lolth's palace.

If Laveth is Killed: her servants flee to other layers of the Abyss. Lolth will be upset that her daughter was slain, and at some point in the future, sends assassins to kill the adventurers.

If the group escapes with a power receptacle, Laveth sends her minions after the group.

Returning Alerian: The elves are forever grateful. Elven bards sing of their heroism.

Final Note From the Adventure:

"Lolth's own vast palace lies at the center of the web, filled with demons, yochlol, and the most powerful drow servants imaginable, rivaling Laveth in power and ambition - for not just anyone can serve in the sanctum of their goddess."