eXputer

QuestmajorMain storyHard

Travel through the Underdark

Explore the Underdark in Act One, uncovering locations, characters, hazards, equipment and branching questlines before continuing toward the Shadow-cursed lands.

RoleMajor Act One exploration route and progression area
StatusAvailable in Baldur's Gate 3
Importancemajor
RewardAccess to Underdark locations, quests, encounters and unique equipment.
  • ActOneThe Underdark is a major Act One area.
  • Region typeSunless caverns and tunnelsA subterranean area beneath Faerûn.
  • Route roleAlternative pathIt offers an alternative route toward later zones such as the Shadow-cursed lands.
  • Known access pointsMultipleKnown entrances include the Shattered Sanctum, Whispering Depths, Zhentarim Hideout and Overgrown Tunnel.
  • Notable settlementsSelunite Outpost and Ebonlake GrottoThe Ebonlake Grotto is inhabited by Myconids.
  • Notable guardianBernardBernard is a mechanical guardian encountered in the region.

This entry describes a broad exploration objective rather than a single linear mission. Exact route order and the full set of encounters depend on the party's exploration.

Key takeaways

The Underdark rewards a careful, exploratory approach rather than a rush to the next zone.

  • Choose from several entrances The Shattered Sanctum, Whispering Depths, Zhentarim Hideout and Overgrown Tunnel can all provide access, allowing different Act One routes to converge in the Underdark.
  • Explore the major settlements The Selunite Outpost, Ebonlake Grotto and Arcane Tower are among the region's notable destinations and should be treated as distinct exploration objectives.
  • Expect environmental danger Dangerous creatures and rare alchemical mushrooms make the Underdark more than a conventional combat area; the subterranean environment is part of the challenge.
  • Look for unique equipment The region is associated with valuable finds including Phalar Aluve, Adamantine equipment from Grymforge, and various rings and amulets.
  • Do not skip local characters Omeluum, Duergar and Myconid leaders are among the characters encountered here, and the region contains branching questlines that reward investigation.

Overview

Travel through the Underdark is a major Act One exploration objective in Baldur's Gate 3, taking the party into a vast network of sunless caverns beneath Faerûn.

The Underdark is a vast, sunless region of caverns and tunnels located deep beneath the surface of Faerûn. In Baldur's Gate 3, it functions as a substantial area rather than a short detour, combining exploration, combat, environmental hazards and several interconnected questlines.

There are multiple ways to enter the Underdark. Known access points include the Shattered Sanctum, the Whispering Depths, the Zhentarim Hideout and the Overgrown Tunnel, so the party may arrive from different directions depending on how it has explored Act One. These entrances make the region a branching alternative path rather than a single linear corridor.

The area contains important destinations including the Selunite Outpost, the Ebonlake Grotto and the Arcane Tower. The Ebonlake Grotto is inhabited by Myconids, while the wider region also brings the party into contact with Duergar and characters such as Omeluum. Thorough exploration is valuable because the Underdark contains rare alchemical mushrooms, significant equipment and secrets connected to branching quests.

The Underdark also presents several demanding encounters. Players may face a Spectator, a Bulette or the mechanical guardian Bernard, while the environment itself creates additional pressure through dangerous creatures and unusual subterranean hazards. The area ultimately prepares the party for later zones such as the Shadow-cursed lands, while offering a distinct atmosphere and gameplay rhythm from the surface.

This page treats Travel through the Underdark as an exploration-focused quest entry. It does not imply that every location, encounter or reward must be completed in one fixed order; the available route and the party's discoveries can vary according to which entrance is used and which local questlines are pursued.

Where this sits

Surface explorationFind a route below Faerûn
The UnderdarkExplore this quest's region
Later zonesContinue toward the Shadow-cursed lands
  1. 1Locate an entranceaccessReach the Underdark through one of the known access points.
  2. ●Survey the cavernsexplorationExplore the sunless tunnels and identify the region's major destinations.
  3. 3Investigate local factionsquestsMeet Myconid and Duergar leaders and speak with characters such as Omeluum.
  4. 4Pursue equipment and secretsoptionalSearch for notable gear, rare mushrooms and branching quest content.
  5. 5Continue onwardprogressionUse the Underdark as an alternative route toward later zones such as the Shadow-cursed lands.

The Underdark is a major Act One route with multiple entrances and several optional discoveries before onward progression.

Requirements

The essential requirement is access to one of the known entrances. The region is dangerous, so preparation for exploration and combat is recommended.

  • RequiredReach an Underdark entranceThe Shattered Sanctum, Whispering Depths, Zhentarim Hideout and Overgrown Tunnel are known access points.
  • RecommendedPrepare for dangerous encountersThe region contains dangerous creatures and challenging bosses, so the party should be ready for sustained exploration and combat.
  • RecommendedBring room for explorationRare alchemical mushrooms, rings, amulets and other significant loot make careful searching worthwhile.
  • OptionalAllow time for local questsThe Underdark contains branching questlines involving Myconids, Duergar and Omeluum.

Objectives

  1. Enter the Underdark through an available access point.The region can be reached through several locations, so the party's initial approach is not fixed.
  2. Explore the major Underdark locations.The Selunite Outpost, Ebonlake Grotto and Arcane Tower are notable destinations within the area.
  3. Investigate the region's inhabitants.Speak with characters including Omeluum and engage with Duergar or Myconid leaders where their questlines intersect the exploration.
  4. Survive the region's encounters and hazards.Dangerous creatures, environmental threats and named encounters such as the Spectator, Bulette and Bernard make survival a central objective.
  5. Search for equipment and secrets.Thorough exploration can reveal Phalar Aluve, Adamantine equipment from Grymforge, rings, amulets and other discoveries.
  6. Continue toward later zones when ready.The Underdark serves as an alternative path toward areas such as the Shadow-cursed lands.Optional

Walkthrough

  1. 01

    Locate an Underdark entrance

    Find a route below the surface

    Begin by reaching one of the known entrances: the Shattered Sanctum, Whispering Depths, Zhentarim Hideout or Overgrown Tunnel. The game does not require a single universal entry route, so use the entrance opened by the party's Act One exploration.

    Location: Act One surface areas

    TipRecord which entrance you used, because the party's first position can change the order in which nearby discoveries are encountered.

  2. 02

    Begin exploration

    Enter the Underdark carefully

    Once below the surface, treat the caverns and tunnels as a large exploration zone rather than a short passage to the next act. Dangerous creatures and environmental hazards can interrupt travel, so advance methodically and keep the party ready for combat.

    Location: The Underdark

    Watch outDo not assume that the subterranean route is safe simply because it is an alternative path.

  3. 03

    Explore the region

    Survey the sunless caverns

    Explore beyond the immediate entrance and map the surrounding tunnels before committing to onward travel. The Underdark's value comes from its combination of locations, secrets, encounters and branching local quests, so a direct push through the region can leave content undiscovered.

    Location: The Underdark

    TipSearch side passages and unusual environmental areas instead of following only the most obvious route.

  4. 04

    Investigate a major location

    Visit the Selunite Outpost

    Make the Selunite Outpost one of the region's exploration targets. It is a named location within the Underdark and helps establish the area's mixture of abandoned, contested and inhabited subterranean spaces.

    Location: Selunite Outpost

  5. 05

    Meet the Myconids

    Reach the Ebonlake Grotto

    Travel to the Ebonlake Grotto and investigate its inhabitants. The grotto is inhabited by Myconids, making it an important place to encounter Myconid leadership and to pursue local developments rather than treating the Underdark as only a combat route.

    Location: Ebonlake Grotto

    TipSpeak with the local leaders before leaving; the area contains branching questlines that reward thorough exploration.

  6. 06

    Explore the Arcane Tower

    Investigate the Arcane Tower

    Include the Arcane Tower in the exploration plan and examine what it offers. The tower is one of the Underdark's notable locations and is associated with the region's environmental puzzles, secrets and unusual encounters.

    Location: Arcane Tower

    Watch outEnvironmental puzzles and hidden discoveries are part of the area's challenge, so do not rush through this location.

  7. 07

    Investigate local questlines

    Speak with Omeluum and local leaders

    Look for Omeluum and the various Duergar or Myconid leaders encountered in the region. These characters are connected to the Underdark's branching quest content, so conversations can be as important as clearing hostile areas.

    Location: Underdark settlements and quest areas

    Missable
  8. 08

    Collect notable discoveries

    Search for rare materials and equipment

    Thoroughly inspect the region for rare alchemical mushrooms, rings and amulets, as well as notable equipment such as Phalar Aluve. Grymforge is particularly important for Adamantine equipment, making careful exploration worthwhile before moving on.

    Location: The Underdark and Grymforge

    TipKeep exploration and loot searches separate from the main travel objective so that optional finds are not overlooked.

    Missable
  9. 09

    Survive major encounters

    Handle the named encounters

    Prepare for challenging encounters including a Spectator, a Bulette and the mechanical guardian Bernard. The source material identifies these as notable bosses or guardians, but their precise order and encounter circumstances can vary with the party's route.

    Location: The Underdark

    Watch outDo not treat every named encounter as a mandatory step in one fixed sequence; explore according to the route available in the current playthrough.

  10. 10

    Progress beyond the Underdark

    Choose when to leave

    After completing the discoveries and local questlines that matter to the party, continue toward later zones such as the Shadow-cursed lands. Leaving early can shorten the route but may mean missing equipment, secrets or branching content.

    Location: The Underdark exit and onward route

    Missable

Mission mechanics

The Underdark is structured around route choice and layered exploration. Because the party can enter through several different locations, there is no single starting position that defines every playthrough. This makes orientation important: the same broad objectives can be reached from different directions, and the order of discoveries is not necessarily fixed.

Environmental danger is a central part of the region's identity. The party must contend with dangerous creatures as well as a variety of rare, alchemical mushrooms. The area also tests players with environmental puzzles, so progress is not limited to defeating enemies; observation and patient investigation are useful tools.

Faction and character interaction gives the region additional depth. The Ebonlake Grotto is inhabited by Myconids, while Duergar and Myconid leaders appear among the local powers. Omeluum is another notable character encountered here. These interactions contribute to branching questlines, which means thorough exploration can produce more than a simple route to the next zone.

Loot provides a practical reason to explore every major destination. Phalar Aluve, Adamantine equipment from Grymforge, rings and amulets are among the valuable discoveries associated with the region. The Underdark therefore works both as an alternative progression route and as a place where a party can acquire distinctive equipment and investigate optional content.

What works and what does not

Strengths

  • Multiple entrances support different Act One routes.
  • The region combines combat, environmental puzzles, faction interactions and exploration.
  • Distinct destinations such as the Selunite Outpost, Ebonlake Grotto and Arcane Tower give the area a strong sense of place.
  • Unique equipment and rare alchemical mushrooms reward careful searching.
  • Branching questlines make local characters and settlements worth investigating.

Weaknesses

  • The number of routes and optional discoveries can make the region difficult to navigate.
  • Dangerous creatures and challenging named encounters can punish an unprepared party.
  • A party that leaves quickly may miss secrets, equipment and local quest content.
  • The order of encounters is not presented here as fixed because it can depend on the chosen entrance and exploration path.

Best uses

  • Use the Underdark as a substantial Act One exploration route.
  • Visit major locations before progressing toward later zones.
  • Combine local character investigation with equipment and secret hunting.

Major encounter typesSpoilers

  1. 1

    Cavern and tunnel exploration

    Starts: Entering the Underdark through any known access point.

    The party moves through a sunless region containing dangerous creatures, environmental hazards and rare mushrooms.

    • Explore methodically rather than assuming the route is a safe corridor.
    • Treat unusual environmental features as possible puzzle or discovery points.
  2. 2

    Named creature encounters

    Starts: Reaching the areas associated with the region's notable bosses.

    The Underdark hosts challenging encounters including a Spectator and a Bulette.

    • Prepare before committing to a major fight.
    • The exact order and circumstances are not treated as universal because the region has multiple approaches.
  3. 3

    Arcane Tower guardian

    Starts: Exploring the Arcane Tower and reaching its mechanical guardian.

    Bernard is identified as a mechanical guardian within the Underdark's notable encounter roster.

    • Investigate the tower's environmental puzzles and secrets rather than focusing only on the guardian.

Boss encountersSpoilers

  • Location
    Various locations in the Underdark
  • Health
    Not specified in the supplied source material

The region's notable encounters include a Spectator, a Bulette and Bernard, the mechanical guardian. Prepare for each encounter as a separate challenge and use the surrounding exploration context to determine when to engage. Exact health values, weaknesses and encounter-specific tactics are not included because they are not supplied here.

Rewards

  • Potential loot and experience from major encounters; exact rewards are not specified in the supplied source material.

Choices and consequencesSpoilers

  • Choose which entrance to use

    The Shattered Sanctum, Whispering Depths, Zhentarim Hideout and Overgrown Tunnel can lead into the Underdark, changing the party's starting position and likely exploration order.

  • Explore local settlements before leaving

    Investigating the Ebonlake Grotto, Myconid leaders, Duergar leaders and Omeluum opens opportunities to engage with the region's branching questlines.

  • Leave without thorough exploration

    The party can continue toward later zones, but may miss secrets, unique equipment, rare mushrooms and optional quest content.

Checklist

  • Reach the Underdark through an available entrance.Known entrances include the Shattered Sanctum, Whispering Depths, Zhentarim Hideout and Overgrown Tunnel.
  • Explore the Selunite Outpost.Include this named location in the regional survey.
  • Visit the Ebonlake Grotto.The grotto is inhabited by Myconids.
  • Investigate the Arcane Tower.The tower is associated with environmental puzzles and secrets.
  • Speak with Omeluum.Omeluum is one of the notable characters encountered in the Underdark.
  • Investigate Duergar and Myconid leaders.Their presence reflects the region's branching local questlines.
  • Search for rare alchemical mushrooms.The Underdark contains a variety of unusual mushrooms.
  • Look for Phalar Aluve.This longsword is among the region's notable loot.
  • Investigate Grymforge for Adamantine equipment.Adamantine equipment is associated with this location.
  • Prepare for the Spectator, Bulette and Bernard.These are among the region's challenging named encounters.Optional
  • Complete optional discoveries before continuing onward.The region can lead toward later zones such as the Shadow-cursed lands.Optional

Collectibles and secrets

  • 01
    Phalar Aluve

    Where: The Underdark

    A notable longsword associated with the region's significant loot.

    Missable
  • 02
    Adamantine equipment

    Where: Grymforge

    Grymforge is associated with Adamantine equipment and is a major reason to explore the area thoroughly.

    Missable
  • 03
    Rare alchemical mushrooms

    Where: Various Underdark caverns and tunnels

    The region contains a variety of rare, alchemical mushrooms that can be found during exploration.

    Missable
  • 04
    Rings and amulets

    Where: Various Underdark locations

    The Underdark contains various rings and amulets among its valuable discoveries.

    Missable

Failure conditions

  • The party is defeated by a dangerous creature or named encounter.The Underdark contains hostile creatures and challenging encounters including the Spectator, Bulette and Bernard.
  • The party leaves before investigating optional locations.Moving onward without thorough exploration can result in missed secrets, equipment and branching quest content.
  • The party overlooks environmental hazards or puzzles.The subterranean region tests players with environmental puzzles and hazards in addition to combat.

On failure

Exact checkpoints and reload behavior are not specified in the supplied source material.

Rewards

  • Phalar Aluve
    A notable longsword associated with Underdark exploration.
  • Adamantine equipment
    Equipment associated with Grymforge.
  • Rings and amulets
    Various pieces of accessory equipment can be found in the region.
  • Rare alchemical mushrooms
    The Underdark contains a variety of rare mushrooms useful as exploration discoveries and alchemical resources.
  • Quest and exploration progress
    Thorough exploration can advance branching questlines and provide a route toward later zones such as the Shadow-cursed lands.

Aftermath

Before continuing onward

The Underdark can serve as an alternative route toward the Shadow-cursed lands, but leaving is not the same as completing everything the region offers. Before progressing, check the major locations, local characters, equipment opportunities and branching questlines that matter to your party.

Trivia

  • The Underdark is located deep beneath the surface of Faerûn.
  • The area provides a different gameplay experience from the surface through its sunless atmosphere, environmental puzzles and subterranean hazards.
  • The Ebonlake Grotto is inhabited by Myconids.
  • The region can be reached through multiple entrances rather than one exclusive route.
  • Bernard is a mechanical guardian, contrasting with the region's dangerous beasts and faction conflicts.

Relationships

setting

  • The UnderdarkLocationThe quest covers exploration of this sunless region beneath Faerûn.

locations

  • Ebonlake GrottoMajor locationMyconids inhabit this notable Underdark settlement.
  • Arcane TowerMajor locationA notable Underdark destination containing environmental puzzles and Bernard.
  • GrymforgeLoot locationAssociated with Adamantine equipment.

characters

  • OmeluumQuest-giverA notable character encountered in the Underdark.

progression

  • Shadow-cursed landsLater zoneThe Underdark offers an alternative path toward this later area.