Underdark

Walkthrough

The area in the order you play it. Tick things off as you go: they tick off in the checklists below too.

1. 1

   Emerging into the Upper Caverns

   When you descend into the Underdark and venture into the open cavern past the Selûnite Outpost gates, follow the western stone terrace to find a singing blade buried in rock. Head further west into the petrified drow graveyard where a floating aberration ambushes you from above, unfreezing the drow wizard Dhourn and his thralls. Defeat the monster and loot Dhourn to claim the Icy Helve component before advancing into the deeper tunnels.

   Phalar Aluve: Stuck inside a stone terrace west of the Selunite Outpost Don't miss

   Tip: Clerics of Eilistraee can draw Phalar Aluve without making any ability check.

   Watch out: Failing both the Strength and Religion checks to draw Phalar Aluve leaves the blade permanently wedged in the stone.

2. 2

   Crossing the Central Chasms

   As you push across the open fungal ridges toward the center of the cavern, stay alert for rumbling earth as a massive burrowing beast stalks the terrain. Fight off or fell the monstrosity when it bursts through the ground, then continue north along the illuminated paths toward the towering fungal colony. Before entering the safe haven, scan the perimeter cliffs to secure the surrounding crossroads.

   Key fight: Bulette

   Tip: Knocking the Bulette down or bursting it with heavy burst damage prevents it from burrowing away to ambush you elsewhere later.

   Watch out: Leaving low-health party members grouped together risks an instant wipe from the Bulette's devastating leap attack.

3. 3

   Brokering Peace in the Myconid Colony

   When you enter the towering fungal haven of Ebonlake Grotto, commune with Sovereign Spaw upon the central mushroom tier to receive a commission to wipe out the duergar invaders. Speak with the poisoned deep gnome Thulla on an upper ledge to cure her affliction, and converse with the Society of Brilliance scholars Blurg and Omeluum regarding your parasite. Recruit the exiled Sovereign Glut from his roost near the entrance so his reanimation spores can aid you in upcoming skirmishes.

   Shadow of Menzoberranzan: From Sovereign Spaw at the Myconid Colony, enter the opened Guardian Treasury alcove at X: 50, Y: -75How: Interact with the pale drow corpse resting in the center of the opened treasuryMissable because: Permanently locked out if you murder Sovereign Spaw before turning in the quest to defeat the duergar Don't miss New

   Tip: Giving Thulla an Antitoxin or casting Lesser Restoration saves her life and rewards you with the Boots of Speed.

4. 4

   Rescuing Baelen in the Bibberbang Gulch

   Venture into the gulch northwest of the fungal colony where the dwarf herbalist Baelen Bonecloak is trapped amid volatile, green exploding fungi. Carefully retrieve Baelen's lost pack with a summoned familiar or spell before clearing him an escape path, then secure the pristine Noblestalk mushroom growing against the far cavern wall. Return to Derryth Bonecloak once the area is safe to decide the fate of the rare harvest.

   Noblestalk: From Baelen Bonecloak in the Bibberbang Gulch, look at the far northwest rock wall at X: -165, Y: -60How: Send a Mage Hand or use telekinesis to pick up the blue mushroom without igniting nearby sporesMissable because: Any exploding Bibberbang spore or fire source completely destroys the mushroom permanently Don't miss New

   Tip: Using an invisible Mage Hand allows you to drag Baelen's pack and the Noblestalk out without triggering a single spore.

   Watch out: Any open flame or detonated Bibberbang bulb triggers a chain explosion that instantly incinerates the unique Noblestalk into useless ash.

5. 5

   Harvesting the Great Sussur Tree

   Follow the western path down into the Dread Hollow, where massive Sussur blooms project an anti-magic field that suppresses all nearby spellcasting. Battle the predatory Hook Horrors and the deranged hermit Filro the Forgotten lurking near the roots to claim the Icy Crystal from his corpse. Climb the high wooden boughs running along the western trunk to strip a sample of Sussur Tree Bark for your masterwork weapon forge.

   Mourning Frost (Very Rare Quarterstaff): Combine the Icy Helve from Dhourn (west of Selunite Outpost), Icy Crystal from Filro the Forgotten (Sussur Tree base), and Icy Metal inside the Myconid Guardian Treasury (unlocked by Sovereign Spaw)How: Combine all three icy components inside your inventory windowMissable because: Lost if Dhourn or Filro's corpses fall into the chasm or if you side with Glut and fail to open Spaw's treasury Don't miss NewSussur Tree Bark: From the Underdark - Sussur Tree Waypoint (X: -50, Y: -138), climb the high western roots of the Great Sussur Tree to X: -15, Y: -140How: Interact with the highlighted bark patch along the central trunk to strip itMissable because: Required for the Masterwork Forge quest in Act 1; inaccessible once traveling onward to Act 2 Don't miss New

   Tip: Martials excel in the anti-magic field; reposition your spellcasters to elevated perches outside the blue aura so they can cast freely.

   Watch out: Filro will command Hook Horrors from above, so avoid lingering clustered beneath the high boughs where they can ambush your backline.

6. 6

   The Fish Cult of the Festering Cove

   Head toward the chasm ledges northeast of the Arcane Tower and south of the Decrepit Village, searching the rock wall near coordinates X: 70, Y: -240 for a path leading downward. Climb down the knotted cragged rock face to uncover a flooded hidden cavern where fish-like Kuo-toa prostrate themselves before an impostor deity. Confront BOOOAL and expose his fraudulent identity or eradicate him to liberate the zealous worshippers.

   Key fight: BOOOAL and the Kuo-toa
   The Festering Cove, a hidden subterranean cove reachable by climbing down cragged rock walls in the chasms near the Arcane Tower, where fish-like Kuo-Toa worship an impostor deity named BOOOALHelmet of Autonomy: On the cliff edge path above the Festering Cove descent at X: 82, Y: -241How: Loot the skeleton lying near the drop-off ledgeMissable because: Easily overlooked prior to climbing down the cragged rock wall Don't miss NewSlippery Chain Shirt: Inside the Festering Cove, jump across the eastern stalagmites to the hidden upper shelf at X: -400, Y: 325How: Pass a DC 10 Perception check to spot the concealed Gilded Chest and lockpick itMissable because: Locked out if you leave the Underdark without exploring the hidden cove Don't miss New

   Tip: Passing the Investigation and Persuasion checks allows you to usurp BOOOAL and turn the entire Kuo-toa flock into your devout allies.

   Watch out: Choosing to appease BOOOAL by sacrificing a companion results in their permanent, irreversible death with no possibility of resurrection.

7. 7

   Clearing the Decrepit Village Slavers

   Make your way down to the decrepit lakeside ruins where Gekh Coal and his duergar slaver patrol lie in ambush among the derelict stone buildings. Engage the slavers, utilizing Sovereign Glut's spore servants to counter Gekh Coal's raised animated corpses and mind-mastery magic. Once the beach is secured, Glut demands that you usurp Sovereign Spaw; execute Glut on the shoreline or agree to his coup before returning to claim the colony's sealed rewards.

   Key fight: Gekh Coal and the Duergar Slavers

   Tip: Shoving or blasting duergar archers off the high wooden walkways into the lower ruins neutralizes their height advantage immediately.

   Watch out: Siding with Glut forces you to slaughter the peaceful Myconid Colony and permanently locks you out of Spaw's Bliss Spores and the Envoy's Amulet.

What you decide here and what it leads to.