TEXT: TOWER 
  TOWER OFOF NECROMANCY
   NECROMANCY
  ICEWIND DALE: RIME
  ICEWIND DALE: RIME OF THE
  OF THE FROSTMAIDEN
  FROSTMAIDEN
  Expanded Content for
  Expanded Content for
  Chapter 7: Doom of Ythryn
  Chapter 7: Doom of Ythryn
  
  Credits
  Writing & Layout: Daniel Kahn
  Cover Art and Cartography: by Nicole Mastrodomenico (@nikodomeniko)
  DUNGEONS & DRAGONS, D&D, Wizards of the Coast, Forgotten Realms, Ravenloft, Eberron, the dragon ampersand, 
  Ravnica and all other Wizards of the Coast product names, and their respective logos are trademarks of Wizards of the 
  Coast in the USA and other countries.
  This work contains material that is copyright Wizards of the Coast and/or other authors. Such material is used with 
  permission under the Community Content Agreement for Dungeon Masters Guild.
  All other original material in this work is copyright 2021 by Daniel Kahn or Nicole Mastrodomenico and published 
  under the Community Content Agreement for Dungeon Masters Guild.
  TOWER OF NECROMANCY
  ICEWIND DALE: RIME OF THE FROSTMAIDEN
  
  3
   INTRODUCTION  |
   INTRODUCTION  |
  Introduction
  T 
  he tower of necromancy was one of eight 
  towers of magic in the ancient floating 
  Netherese city of Ythryn. Now the tower, along 
  with the city, lies trapped in a frozen tomb. The 
  wizards of this great tower are either long dead 
  or have lost their minds to madness. Yet the tower still 
  holds powerful magic waiting to be tapped.
  What’s This All About?
  Chapter 7: Doom of Ythryn is the climax of Icewind 
  Dale: Rime of the Frostmaiden. This epic chapter has 
  characters investigating the ancient city of Ythryn for 
  a way to put an end to the Everlasting Rime. The basic 
  outline of this chapter is the following:
  • Learn the Rite of the Arcane Octad, in order to get 
  through a force field protecting the central tower of 
  Ythryn (the Spire of Iriolarthas).
  • Kill the Demilich Iriolarthas, who lives in the Spire 
  of Iriolarthas and is attuned to the Ythryn Mythallar.
  • Attune to the Ythryn Mythallar, which allows 
  characters to end the Everlasting Rime.
  This supplement is one of several short expansions to 
  the locations in Ythryn (more can be found at this link) 
  with the following objectives:
  • Expand on the Eight Arcane Towers, making each 
  one its own mini-dungeon adventure with exciting 
  challenges and clear direction for the DM.
  • Provide Detailed Maps, for an immersive experience 
  in person or on a virtual tabletop, rather than a brief 
  'theatre-of-mind' scene.
  This supplement presents the events that occur in 
  the Tower of Necromancy as an alternate to those 
  described on page 246–247 of Icewind Dale: Rime of 
  the Frostmaiden. Additionally, the process for the Ritual 
  of Brain Transfer described within differs from what 
  is described on page 249 of the book. As always, it is 
  up to you how much of the content you want to use. It's 
  perfectly fine to use some parts of this supplement while 
  discarding others, or simply let the ideas presented here 
  inspire new ideas of your own. This supplement assumes 
  a party of 4–6 characters of 9–11th level. 
  History of High Necromancer Cadavix 
  High Necromancer Cadavix was a powerful necromancer 
  wizard in Ythryn. Through alchemical and necromantic magic, 
  Cadavix developed a way to preserve a person's brain in a jar 
  so that they could live forever. Cadavix was the only wizard in 
  Ythryn with the skill and knowledge to successfully complete 
  the Ritual of Brain Transfer. 
  During his life, Cadavix shared a secret love with High 
  Enchanter Ivira. The two cared deeply for each other, but 
  due to their positions of power, they kept their relationship 
  hidden.    
  When Ythryn began to fall, Cadavix cast a magic jar spell 
  on himself, safeguarding his soul in a large durable emerald. 
  Unfortunately, Cadavix's body was too broken to return to 
  and no living humanoids found his emerald in the aftermath. 
  As such, Cadavix remains in the emerald to this day, with the 
  hope of seeing his love once more driving him to live.   
  Adventure Summary
  After their arrival at the Tower of Necromancy, 
  characters will meet a brain in a jar who is trying to 
  learn how to extract the brains of others. The brain 
  suffers from delusions that it is still human and that 
  everything is mostly normal. The characters can 
  befriend the brain by helping it, or potentially cause it 
  to become violent if they draw too much attention to its 
  true reality. After dealing with the brain in the jar, the 
  characters can proceed up to the top of the tower where 
  they find the remains of High Necromancer Cadavix, 
  who has been trapped in a magic jar spell of his own 
  design since the Ythryn fell. Cadavix knows the Rite of 
  the Arcane Octad, but needs the party's help before he 
  gives it to them. Cadavix attempts to use the magic jar 
  spell to possess the body of one of the party members in 
  order to bring his own body back to life and discover the 
  fate of his lover. 
  Running the Adventure
  The following sections describe what the characters find 
  at the Tower of Necromancy in Ythryn. Location Y15. 
  Tower of Necromancy refers to the Map 7.2 Necropolis 
  of Ythryn on page 236–237 of Icewind Dale: Rime of the 
  Frostmaiden (see a Change of Venue below). Locations 
  within the tower refer to the map on pages 4 and 5 of this 
  document.
  A Change of Venue 
  In Icewind Dale: Rime of the Frostmaiden, the Tower of 
  Necromancy is located at Y18 as the tower has collapsed. 
  In this supplement, the tower is still standing and is located 
  at Y15, instead of Y18. If you used the Tower of Divination 
  supplement, Y15 is no longer the Observatory, as the Tower of 
  Divination and the Observatory were combined and located at 
  Y11. If you are not using the Tower of Divination supplement, 
  and the Observatory is still located at Y15, you can place the 
  Tower of Necromancy in any unmarked structure on Map 7.2.   
  Y15. Tower of Necromancy
  As the characters approach the tower, you can read the 
  following:
  A short conical tower supported by arched buttresses stands 
  on the edge of the city. On the outward-facing side of the 
  tower is a eerie green-glowing arcane symbol. A metal door 
  leads into the base of the tower.
  Characters proficient in Arcana, or who succeed on 
  a DC 15 Intelligence (Arcana) check, recognize the 
  arcane symbol as representing the magical school of 
  necromancy. 
  Aura of Repose. A detect magic spell cast here reveals 
  an aura of necromantic magic. While a dead body is 
  within 30 feet of the Tower of Necromancy, it is under 
  the effect of a gentle repose spell, which permanently 
  emanates from the tower. Casting a dispel magic spell 
  suppresses the effect for 1 hour. 
  Door. The door to the tower is closed, but unlocked. 
  Characters who listen at the door to the tower and make 
  a successful DC 10 Wisdom (Perception) check, can 
  hear a faint scuttling sound from within. 
  Lighting. The interior of the tower is dimly lit by green 
  luminescent fungus called ormu. The fungus is abundant 
  enough that its glowing pigment can be harvested.
  
  4  |  RUNNING THE ADVENTURE
   |  RUNNING THE ADVENTURE
  Y15A.
  Y15A.
  Tower of Necromancy
  Tower of Necromancy
  Y15A. Operating Room 
  When characters enter the tower, you can read the 
  following:
  A caustic smell assaults your nose as you enter this circular 
  chamber. Gray disembodied hands skitter across the 
  room, which is lit by an eerie green glow. Chairs are neatly 
  arranged around the room, some containing seated bodies 
  missing their hands. Various pieces of surgical equipment 
  sit on tables and shelves around the room. A one-eyed 
  creature is restrained to a bloodstained bed in the center 
  of the room. Near the table, a brain floats in a liquid-filled 
  cylinder, with a crude face drawn in paint on the glass. 
  The brain, once a man named Lawrynce, was an 
  apprentice of the High Necromancer Cadavix. At the 
  hands of his master, Lawrynce willingly underwent 
  the Ritual of Brain Transfer to become a brain in a 
  jar. Having never been properly taught by his master, 
  has been unsuccessfully practicing the ritual to turn 
  creatures into brains in jars on his own. When the party 
  arrives, Lawrynce is about to attempt the ritual on a 
  restrained nothic. Sixteen crawling claws inhabit the 
  room and are under Lawrynce's control. The crawling 
  claws originated from dead wizards of the tower.
  Insanity. Lawrynce's time as a brain in a jar combined 
  with the trauma from finding the dead body of his master 
  upstairs has caused him to suffer from delusions about 
  his physical state. Lawrynce no longer believes that he 
  is a brain in a jar and does strange things like wearing 
  a lab-coat hanging from his jar, floating around with 
  crawling claws at the end of his sleeves 
  as if he had hands, and drawing 
  facial expressions on the 
  glass with paint. If characters 
  suggest that Lawrynce is a 
  disembodied brain, he begins 
  to grow irritable. If reminded 
  of his form three times, he 
  suffers a psychic break and 
  becomes hostile towards the 
  characters. A successful DC 
  15 Charisma (Deception) 
  check can calm him down if 
  hostilities arise.
  Ritual of Brain Transfer. 
  Lawrynce knows the arcane 
  principles of the necromantic 
  ritual to create a brain in a jar, 
  but lacks the precision and 
  medical skills to keep the brain 
  intact during surgery. Looking 
  for any opportunity to advance 
  his studies, he asks for the 
  party's assistance in the task. 
  In order to successfully perform 
  the brain in a jar ritual, the 
  characters must complete the 
  following steps for Lawrynce:
  • Successfully incapacitate the restrained 
  nothic without damaging the body. Lawrynce 
  recommends the use of the poisons stored on the 
  shelves in the room (see treasure below). Spells like 
  hypnotic pattern or hold monster also work.
  • Make a successful DC 15 Wisdom (Medicine) check to 
  identify safe places to perform surgical cuts to extract 
  the brain without damaging it. A creature proficient 
  with alchemist's supplies has advantage on this check.
  • Make a successful DC 15 Dexterity check to physically 
  make the surgical cuts and perform the extraction 
  without damaging the brain. A creature proficient with 
  alchemist's supplies has advantage on this check.
  If the process is successful, Lawrynce completes 
  the necromantic component of the ritual, killing the 
  nothic and creating another (very confused) brain in 
  a jar. Lawrynce offers to repeat the process for any 
  characters who wish the partake. The ritual results in 
  the death and liquefaction of the subject’s body. At your 
  discretion, the process can be used on the body of a 
  player character that has died within the last 24 hours 
  (see Troubleshooting section for additional suggestions). 
  Treasure. A search of the room yields a set of 
  alchemist's supplies, three doses of carrion crawler 
  mucus, and three doses of torpor. 
  Roleplaying Lawrynce 
  Lawrynce is intended to be a bit of comic relief from an 
  otherwise spooky location (and chapter). Here are a few 
  suggestions for how to roleplay him:
  • Lawrynce is chaotic neutral in that he is neither good nor 
  evil, but is generally bringing a bit more chaos into the 
  world than order by trying to revitalize the Ritual of Brain 
  Transfer.
  • Lawrynce has had thousands of years to himself so is 
  desperate to talk to someone. You can have Lawrynce 
  ramble on a bit whenever answering questions, simply 
  reveling in the ability to converse with people.
  • Lawrynce uses the crawling claws in the Tower of 
  Necromancy as helpers. He refers to the hands based on 
  if they are right or left and who they belonged to. He might 
  say "Thank you Right Glaima" or "Left Tyran, can you please 
  put a kettle on for our guests?" 
  • Seeing the body of his master after the fall of Ythryn has  
  Lawrynce stuck in the first stage of grief: denial. If asked 
  about the High Necromancer, he says that his master is 
  upstairs busily working. He skirts any subject relating to the 
  last time he's seen his master. 
  • Lawrynce uses his mage hand cantrip to attach his lab coat 
  to his jar to give the appearance that he is wearing it. He 
  also uses his mage hand to paint crude facial expressions 
  on the front of his jar - something he does subconsciously. 
  Up To 
  Up To 
  Y15B
  Y15B
  
  5
   RUNNING THE ADVENTURE  |
   RUNNING THE ADVENTURE  |
  Y15B.
  Y15B.
  Y15B. Cadavix's Quarters
  When characters reach the top floor, you can read:  
  Books, overturned tables, and bones of varying shapes and 
  sizes lie strewn about the floor of this small round chamber, 
  all covered in green luminescent fungi. A well preserved 
  body lies twisted and broken on the floor. In the corner of 
  the room, the glint of large green gemstone can be seen 
  half-buried by the bones. 
  The body belongs to High Necromancer Cadavix. The 
  body does not appear to have aged or decayed, and a 
  successful DC 12 Wisdom (Medicine) check reveals that 
  the cause of death was bludgeoning from Ythryn's fall. 
  The bones lying around the room were part of Cadavix's 
  exquisite fossil collection from various rare creatures, 
  which a successful DC 12 Intelligence (Nature) check 
  confirms. 
  High Necromancer Cadavix's soul is trapped inside 
  the large emerald (worth 500 gp) as part of a magic jar 
  spell that he cast when Ythryn fell. His body is dead 
  and broken, so he cannot safely return to it. When the 
  party enters the room, Cadavix quickly assesses his 
  options and attempts to possess the body of one of the 
  characters, with a preference towards those who are not 
  obviously charismatic. The target of the possession must 
  make a successful DC 17 Charisma saving throw or have 
  their soul trapped in the large emerald and have High 
  Necromancer Cadavix possess their body. A creature 
  that resists this saving throw cannot be targeted again 
  for 24 hours. Cadavix will immediately try another 
  character if the first resists saving throw until no viable 
  targets remain. If the character fails the saving throw, 
  provide the player with the information from Handout A.
  Developments. Above all else, Cadavix wants to find 
  out the fate of his love, High Enchanter Ivira. If Cadavix 
  has successfully possessed a player character, he will 
  grab the emerald and announce himself to the party in 
  Loross, which professor skant translates. 
  Greetings. I am High Necromancer Cadavix of the Ythryn. I 
  know not how much time has passed since the city fell from 
  the sky, but I need to find someone. I will relinquish this 
  body back to its owner if you permit me to raise mine from 
  the dead and begin my search.  
  Without waiting for much reply, Cadavix searches 
  the room for a 500 gp diamond, which he locates after 
  1 minute. A character that makes a successful DC 20 
  Intelligence (Investigation) check and is searching for a 
  diamond, locates it before he does. 
  After locating the diamond, Cadavix will begin casting 
  raise dead for the next hour (the Aura of Repose makes 
  this possible). If he believes he may be interrupted before 
  beginning he will state, "I will destroy the body I possess 
  if you defy me." A successful DC 20 Wisdom (Insight) 
  check reveals that he does not have much heart behind 
  the threat and is more anxious than aggressive. If he is 
  interrupted before the hour has passed, the diamond is 
  consumed and Cadavix grows increasingly more anxious 
  and states, "If you will not let me have my body, then 
  this body shall suffice until my business is concluded." 
  Cadavix holds on to the emerald used for the magic jar 
  spell for safe keeping. 
  If at any point the party asks for a line of the Rite 
  of the Arcane Octad, Cadavix offers to tell them the 
  seventh line after they help him discover the fate of High 
  Enchanter Ivira. If the party helps him, he will share 
  the line, “Seventh, trace a circle with the ashes of the 
  dead.” Cadavix's body will also give the line of the Rite if 
  questioned under the effect of a speak with dead spell.
  After raising his own body from the dead or resigning 
  himself to keep the body he has possessed, Cadavix 
  will make his way to the Tower of Enchantment. A stat 
  block is provided in the back of this supplement for High 
  Necromancer Cadavix.  
  Other Information. Because the party has this unique 
  opportunity to speak with someone who lived in Ythryn, 
  they may have a lot of questions. You can have Cadavix's 
  memory be hazy after 2000 years, so he cannot provide 
  too many other details outside of the Ythryn Lore. If the 
  party asks about the Ythryn mythallar, you can have 
  Cadavix share where it is located and that the last person 
  attuned to it was his master Iriolarthas, who resided in 
  the central spire of the city. 
  Romantic Tragedy. If High Enchanter Ivira dies (as 
  described on page 256 of Icewind Dale: Rime of the 
  Frostmaiden) or is found dead, Cadavix is overcome by 
  grief, wishing to join his love in the afterlife. If he is in 
  his own body, he uses a powerfully augmented version 
  of the life transference spell to end his own life and 
  heal an injured character. If he has possessed a body, 
  he destroys the emerald used for the magic jar spell, 
  returning the possessed character to their body, and 
  ending his own life. Before he does so, he shares the 
  seventh line of the Rite of the Arcane Octad, entrusting 
  the characters with the legacy of the rite. 
  Treasure. A search of Cadavix's quarters yields 
  several illegible tomes, 500 lbs of fossils worth a total of 
  10,000 gp (to the right buyer), a 500 gp diamond (if not 
  already found and consumed by Cadavix's raise dead 
  spell), a 500 gp emerald (used for the magic jar spell), a 
  staff made from a dragon wyrmling's spine, which can 
  be used as a spellcasting focus, and a libram of souls 
  and flesh. Cadavix's spellbook can also be found, but has 
  faded over the years and is no longer usable. A search 
  of Cadavix's body yields a ring of sound mind (a gift 
  from Ivira). Characters who make a successful DC 15 
  Intelligence (Investigation) check discover a love letter 
  from Ivira to Cadavix. The letter is located in the folds of 
  a book and is made out of exquisite pink paper that has 
  withstood the test of time. The contents of the letter are 
  written in the back of this supplement and provided in 
  handout form with this download as Handout B.
  Down To 
  Down To 
  Y15A
  Y15A
  
  6  |  RUNNING THE ADVENTURE
   |  RUNNING THE ADVENTURE
  Magic Items
  Libram of Souls and Flesh
  Wondrous Item, rare (requires attunement by a wizard)
  With covers made of skin and fittings of bone, this tome 
  is cold to the touch, and it whispers faintly. When found, 
  the book contains the following spells, which are wizard 
  spells for you while you are attuned to the book: animate 
  dead, circle of death, false life, finger of death, speak with 
  dead, summon undead (appears in Tasha's Cauldron of 
  Everything), vampiric touch. It functions as a spellbook 
  for you.
  While you are holding the book, you can use it as a 
  spellcasting focus for your wizard spells.
  The book has 3 charges, and it regains 1d3 expended 
  charges daily at dawn. You can use the charges in the 
  following ways while holding it:
  • If you spend 1 minute studying the book, you can 
  expend 1 charge to replace one of your prepared 
  wizard spells with a different spell in the book. The 
  new spell must be of the necromancy school.
  • As an action, you can expend 1 charge to take on a 
  semblance of undeath for 10 minutes. For the duration, 
  you take on a deathly appearance, and undead 
  creatures are indifferent to you, unless you have 
  damaged them. You also appear undead to all outward 
  inspection and to spells used to determine the target’s 
  status. The effect ends if you deal damage or force a 
  creature to make a saving throw.
  Ring of Sound Mind
  Wondrous Item, rare
  This ring is made of gold with rose-quartz inlays.
  While wearing this ring, you have advantage on saving 
  throws against being charmed.
  Mundane Items
  Carrion Crawler Mucus (Contact). 
  This poison must be harvested from a dead or 
  incapacitated carrion crawler. A creature subjected 
  to this poison must succeed on a DC 13 Constitution 
  saving throw or be poisoned for 1 minute. The poisoned 
  creature is paralyzed. The creature can repeat the saving 
  throw at the end of each of its turns, ending the effect on 
  itself on a success.
  Ormu
  A bioluminescent green moss that grows in warm 
  and damp areas, ormu is particularly common near 
  steam tunnels and vents. It sheds dim light in a 5-foot 
  radius, and can be harvested, dried, and made into a 
  phosphorescent powder or pigment.
  Torpor (Ingested). 
  A creature subjected to this poison must succeed on a 
  DC 15 Constitution saving throw or become poisoned for 
  4d6 hours. The poisoned creature is incapacitated.
  Handouts
  Player handouts are described below.
  Handout A
  Handout A describes information that a player needs to 
  know while possessed by Cadavix. The information is on 
  a separate sheet included with this download.
  Handout B
  Handout B is the contents of the letter from Ivira to 
  Cadavix. The letter is text is provided below and as a 
  separate handout sheet included with this download.
  My Dear Cadavix,
  There is no sending spell that can contain the amount of 
  affection I feel for you. You’re the only person who I feel 
  has ever seen the real me. Though I suppose I should not 
  be surprised that a necromancer would be the one to see 
  past the glamour and to the soul within. With this letter 
  I give you a ring as testament of my feelings for you: the 
  ring has the power to make its wearer resistant to the 
  charms of a wily enchantress like me. This way, you will 
  always know that what we have is real, and true. I’ll meet 
  you at the Music Hall during the next Chain Lightning 
  Tournament.
  With all my heart,
  Ivira
  Conclusion
  Once Cadavix shares his line of the Rite of the Arcane 
  Octad with the party, their business with the Tower of 
  Necromancy is concluded. The party may return for 
  the Ritual of Brain Transfer or to collect a poison to 
  use for Step 8 of the Rite of the Arcane Octad. From 
  here, the party may head to Y20. Tower of Evocation if 
  they are looking for more lines of the Rite. If the party 
  successfully completed the Ritual of Brain Transfer on 
  the nothic, the new brain in a jar either becomes friends 
  with Lawrynce or leaves in search of its own building to 
  haunt.
  Troubleshooting
  Changing uncomfortable topics. In this adventure, the 
  NPC Cadavix ends his life after finding out the fate of 
  his love. If this topic is uncomfortable or inappropriate 
  at your table, you can have Cadavix be so overcome with 
  grief that he either returns to the emerald to be alone or 
  leaves Ythryn forever in his own body.
  Changing the nothic. You can substitute the nothic 
  strapped to the table with a drow (or another Underdark 
  dwelling humanoid) or one of Avarice's cultists. 
  Dealing with possession. Not all players or parties 
  will enjoy deception between players or possession 
  of their character. You can selectively choose a player 
  character to be targeted based on which player you think 
  may be willing to go along with the ruse. If a player 
  expresses worry or seems unhappy with the situation, 
  you can have Cadavix state that he only intends to 
  possess the body until he completes his goals. 
  Players as brains in jars. If a player character 
  undergoes the Ritual of Brain Transfer, you can have 
  them simply change their character's race to Warforged, 
  as their brain is placed on top of a semi-mechanized 
  body. Alternatively, a spellcasting character may be able 
  to continue as a floating brain in a jar, retaining access 
  to all of their spells, class features, Int, Wis, and Cha 
  scores, but otherwise using the brain in a jar stat block.
  Using poisons for the Rite of the Arcane Octad. As 
  written, Step 8 of the Rite of the Arcane Octad requires 
  a creature to "Stand inside the circle and consume 
  poison," but the book does not indicate where characters 
  might find poison within Ythryn. This supplement 
  intentionally added carrion crawler mucus and tupor 
  to the Operating Room of the Tower of Necromancy to 
  address this issue. 
  
  7
   MONSTERS  |
   MONSTERS  |
  High Necromancer Cadavix
  High Necromancer Cadavix
  Medium humanoid (human), neutral evil
  Armor Class 12 (15 with mage armor)
  Hit Points 66 (12d8 + 12)
  Speed 30 ft.
   
   
  STR 
  DEX 
  CON 
  INT 
  WIS 
  CHA
   9 (-1) 
  14 (+2) 
  12 (+1) 
  20 (+5) 
  12 (+1) 
  11 (+0)
  Saving Throws Int +9, Wis +5
  Skills Arcana +9, History +9
  Damage Resistances necrotic
  Senses passive Perception 11
  Languages Draconic, Elvish, Loross
  Challenge 9 (5,000 XP)
  Spellcasting. The necromancer is a 12th-level spellcaster. Its 
  spellcasting ability is Intelligence (spell save DC 17, +9 to hit with 
  spell attacks). The necromancer has the following wizard spells 
  prepared:
  Cantrips (at will): chill touch, dancing lights, mage hand, mending
  1st level (4 slots): false life,* mage armor, ray of sickness*
  2nd level (3 slots): blindness/deafness,* ray of enfeeblement,*  web
  3rd level (3 slots): bestow curse,* dispel magic, vampiric touch*
  4th level (3 slots): blight,* dimension door, life transference*
  5th level (2 slots): cloudkill, raise dead*
  6th level (1 slot): magic jar*
  *Necromancy spell of 1st level or higher
  Grim Harvest (1/Turn). When necromancer kills a creature that is 
  neither a construct nor undead with a spell of 1st level or higher, 
  the necromancer regains hit points equal to twice the spell’s level, 
  or three times if it is a necromancy spell.
  Actions
  Withering Touch. Melee Spell Attack: +7 to hit, reach 5 ft., one 
  creature. Hit: 5 (2d4) necrotic damage.
  Crawling Claw
  Crawling Claw
  Tiny undead, neutral evil
  Armor Class 12
  Hit Points 2 (1d4)
  Speed 20 ft., climb 20 ft.
   
   
  STR 
  DEX 
  CON 
  INT 
  WIS 
  CHA
   13 (+1) 
  14 (+2) 
  11 (+0) 
  5 (-3) 
  10 (+0) 
  4 (-3)
  Damage Immunities poison
  Condition Immunities charmed, exhaustion, poisoned
  Senses blindsight 30 ft. (blind beyond this radius), passive 
  Perception 10
  Languages understands the languages of its creator but can’t 
  speak
  Challenge 0 (10 XP)
  Turn Immunity. The claw is immune to effects that turn undead.
  Actions
  Claw. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 
  3 (1d4 + 1) bludgeoning or slashing damage (claw’s choice).
  Monsters
  Lawrynce (Brain in a Jar)
  Lawrynce (Brain in a Jar)
  Small undead, chaotic neutral
  Armor Class 11 (natural armor)
  Hit Points 55 (10d6 + 20)
  Speed 0 ft., fly 10 ft. (hover)
   
   
  STR 
  DEX 
  CON 
  INT 
  WIS 
  CHA
   1 (-5) 
  3 (-4) 
  15 (+2) 
  19 (+4) 
  10 (+0) 
  15 (+2)
  Saving Throws Int +6, Cha +4
  Damage Immunities poison
  Condition Immunities exhaustion, paralyzed, poisoned, prone
  Senses blindsight 120 ft. (blind beyond this radius); see also 
  “Detect Sentience” below, passive Perception 10
  Languages Draconic, Loross
  Challenge 3 (700 XP)
  Detect Sentience. The brain can sense the presence and location 
  of any creature within 300 feet of it that has an Intelligence of 3 or 
  higher, regardless of interposing barriers, unless the creature is 
  protected by a mind blank spell.
  Innate Spellcasting (Psionics). The brain’s innate spellcasting 
  ability is Intelligence (spell save DC 14, +6 to hit with spell 
  attacks). It can innately cast the following spells, requiring no 
  components:
  At will: chill touch (see “Actions” below), detect thoughts, mage 
  hand, zone of truth
  3/day each: charm person, hold person
  1/day each: compulsion, hold monster, sleep (3rd-level version), 
  Tasha’s hideous laughter
  Magic Resistance. The brain has advantage on saving throws 
  against spells and other magic effects.
  Unusual Nature. The brain doesn’t require air, food, drink, or 
  sleep.
  Actions
  Chill Touch (Cantrip). Ranged Spell Attack: +6 to hit, range 120 
  ft., one creature. Hit: 13 (3d8) necrotic damage, and the target 
  can’t regain hit points until the start of the brain’s next turn. If the 
  target is undead, it also has disadvantage on attack rolls against 
  the brain until the end of the brain’s next turn.
  Mind Blast (Recharge 5–6). The brain magically emits psychic 
  energy in a 60-foot cone. Each creature in that area must succeed 
  on a DC 14 Intelligence saving throw or take 17 (3d8 + 4) psychic 
  damage and be stunned for 1 minute. A creature can repeat the 
  saving throw at the end of each of its turns, ending the effect on 
  itself on a success.
  
  A Dan Kahn 
  Compendium 
  We hope you’ve enjoyed the content in this 
  compendium. If you find any errors, have a good 
  idea, or just want to get in touch, you can reach out 
  to Dan Kahn at leprekahn7@gmail.com. 
  Looking for more? Get the rest of Dan Kahn's 
  Ythryn Towers of Magic here!
  More from Dan Kahn:
  Tomb of Annihilation - Complete DM's Bundle
  Rime of the Frostmaiden - Adventure Bundle
  Rime of the Frostmaiden - Revel's End Prison Break
  Out of the Abyss - 'The Fall of Cyrog'
  
  Handout A
  You have been possessed by High Necromancer Cadavix. 
  • Your Soul. Your character's soul has been ripped from their body and trapped inside the large gemstone. Your 
  character's soul can perceive from the emerald using their own senses, but they can't move, communicate, or take 
  actions at all.
  • Your Body. Your character's body is now inhabited by a 2000-year-old necromancy wizard named High Necromancer 
  Cadavix, who you are now role-playing. 
  • Cadavix will grab the emerald that your soul is trapped in with the emerald, keep it close, and protect it from harm.
  • Cadavix knows there's a 500 gp diamond in the room that he kept for emergencies. He will first try to locate it, and 
  then cast raise dead on his body. If he is successful, he will return to his own body and return you to yours.
  • Cadavix's goal is to discover the fate of his lover, High Enchanter Ivira in the Tower of Enchantment.
  • The tower has an aura that causes all bodies within it to be under the effect of a gentle repose spell.
  • Cadavix doesn't want to harm the party if he doesn't have to and will reveal that he has possessed one of their 
  friends if he thinks it will help ensure their cooperation. 
  A creature possessed by High Necromancer Cadavix has the following ability score modifications and class features:
  • Ability Scores. You retain your Strength, Dexterity, and Constitution scores.
  • Your Intelligence score becomes 20 (+5) and it is proficient in Intelligence saving throws (+9). 
  • Your Wisdom score becomes 12 (+1) and it is proficient in Intelligence saving throws (+5). 
  • Your Charisma score becomes 11 (+0).
  • Grim Harvest. Once per turn when you kill one or more creatures with a spell of 1st level or higher, you regain hit 
  points equal to twice the spell’s level, or three times its level if the spell belongs to the School of Necromancy. You 
  don’t gain this benefit for killing constructs or undead.
  • Inured to Undeath. You have resistance to necrotic damage, and your hit point maximum can’t be reduced.
  • Languages. You speak Draconic, Elvish, and Loross.
  • Spellcasting. You are a 12th-level spellcaster. Your spellcasting ability is Intelligence (spell save DC 17, +9 to hit with 
  spell attacks). You have the following wizard spells prepared:
  • Cantrips (at will): chill touch, dancing lights, mage hand, mending
  • 1st level (4 slots): false life,* mage armor, ray of sickness*
  • 2nd level (3 slots): blindness/deafness,* ray of enfeeblement,*  web
  • 3rd level (3 slots): tongues, dispel magic, vampiric touch*
  • 4th level (3 slots): blight,* dimension door, life transference*
  • 5th level (2 slots): cloudkill, raise dead*
  • 6th level (0 slots): magic jar*
  *Necromancy spell of 1st level or higher.
  
SOURCE: textdata/thevault/Dungeons & Dragons [multi]/Official Content Expanded/Icewind Dale - Rime of the Frostmaiden/Ythryn Expanded Towers of Magic - Bundle/Tower of Necromancy.pdf