In the chilling depths of Baldur’s Gate: Descent into Avernus, the encounter with Flennis in the Dungeon of the Dead Three is among the first true tests for lowlevel adventurers. As a Myrkulworshipping necromancer known as the Master of Souls, Flennis orchestrates a terrifying showdown with undead horrors and powerful necrotic magic. This guide explores her role, location, tactics, and narrative significance as DMs navigate one of the campaign’s early highlights in Avernus.
Who Is Flennis?
Cult Leader and Necromancer
Flennis serves as a highranking follower within the Cult of the Dead Three in Baldur’s Gate. She holds the title Master of Souls and acts as the Myrkulian representative within the cult’s leadership. She’s a pale, lanky figure whose ambition edged toward undeath, and she spends time experimenting with corpse manipulation and necromantic rituals within her lair.
Role in the Dungeon of the Dead Three
Found deep in the Dungeon of the Dead Three (Area D13, the Morgue), Flennis commands skeletal rats and Corpsedamp zombies. She holds a spellbook and key prophecy handouts, making her a narrative anchor for players investigating cult activities.
The Morgue Encounter: Locating Flennis
Dungeon Location
The Morgue resides past the cult bathhouse and the Necromites’ room, inside a dimly lit, claustrophobic chamber. PCs enter from an adjoining hallway, where Flennis hunched over corpse manipulation apparatus, immersed in dark necromantic rites.
Signs and Foreshadowing
DMs can foreshadow her presence by mentioning undead rumors, reanimated bodies, and whispers of ritualistic violence tied to Myrkul. NPCs or environmental descriptions may reveal her as a soul experimenter deep in Baldur’s Gate’s seedy underbelly.
Combat Tactics and Abilities
Spellcasting Threats
Flennis is capable of casting a Fireballlike spell that deals necrotic damage. While dangerous to lowlevel parties, some DMs choose to hold back this ability if the PCs are only level 2 to prevent an instant wipe.
Undead Allies
She commands skeletal rats and Corpsedamp zombies, often using Darkness to obscure the field and full advantage of her minions. Triggering a gas leak or unleashing undead makes the encounter harrowing and memorable.
Suggested Combat Flow
- Surprise round: Flennis may begin casting or releasing gas, summoning undead.
- Round 1: PCs react, launching ranged attacks or going into melee.
- Subsequent rounds: Flennis may use Darkness or necrotic Fireball once, then rely on summoned undead.
Adjusting Difficulty and Level Balance
Recommended Levels
Flennis’s encounter is written for PCs around level 23, but many DMs elevate parties to level 3 to balance survivability. Without adjustment, her Fireball can instantly incapacitate spellcasters.
DM Options
- Limit Flennis’s spellcasting to nonFireball options or reduce spell damage.
- Reduce the number of summoned undead to ease early waves.
- Provide environmental cues or lowstakes puzzles to weaken her before the full assault.
Narrative Impact and Roleplay Opportunities
Development Through Lore
Flennis carries key handouts such as the Missive of the Hidden Lord and leads the ritualistic murders tied to the Vanthampur family. Interrogating her or recovering those props helps players piece the larger conspiracy.
Player Agency
Allowing PCs to either confront her violently or investigate her work nonlethally enriches the experience. Discovery of corpsestudying tools, ripped ritual notes, or undead experiments may inform players about Myrkul’s influence and the cult’s internal structure.
After the Encounter
Consequences of Her Fate
Slaying Flennis opens access to deeper levels of the dungeon and grants PCs access to her spellbook or notes. If captured or spared, she could offer other clues or escape, complicating future sessions.
Setting Up Future Threats
Her defeat signals escalation: now the cult’s remaining leaders Yignath and Vaaz become more prominent threats. Mortlock Vanthampur may react depending on PCs’ handling of Flennis, opening diplomatic or espionage threads.
Tactical Tips for DMs
- Use low light, choking atmosphere, and slow reveals to build tension.
- Limit spells if PCs are low level; emphasize minions and environment.
- Reward investigation with lore handouts or keys to secret doors.
- Seed rumors beforehand: wandering undead, vanished locals, cult symbols.
Flennis’s descent into Avernus is a fierce and meaningful encounter in the early stages of Descent into Avernus. She combines necromancy, undead allies, and cult intrigue to create a chilling first test for aspiring heroes. Her location in the Morgue, her spellcasting capabilities, and the narrative weight she carries make her a memorable ‘boss’ in the Dungeon of the Dead Three. Whether you run her as a deadly threat or a harbinger of deeper mysteries, Flennis helps cement the tone of infernal danger and moral consequence from the start of the campaign. Use this guide to orchestrate the encounter with tension, balance, and roleplaying flair that sets players on the dark path ahead.