As one of the earliest bosses in Baldur’s Gate 3, Phase Spider Matriarch belongs to the monster category and is one of the most difficult ones in the whole game (Phase Spider race). You will encounter this monster during your visit to the Whispering Depths area of Blighted Village during Search the Cellar quest. Phase Spider Matriarch is an optional boss (even during the quest) but we highly recommended taking it down for some sweet rewards.
In this guide, we will tell you about the exact location, strengths and weaknesses of Phase Spider Matriarch in Baldur’s Gate 3. She is one of the most difficult early-game bosses and can wipe out your whole party in an instant. Make sure to read all the sections carefully and our character creation guide to use your character’s strengths against Phase Spider Matriarch in BG3.
Baldur’s Gate 3 Phase Spider Matriarch location

Phase Spider Matriarch is present inside the Whispering Depths dungeon (X: 540, Y: -354). This dungeon can only be accessed through a broken house in Blighted Village. Once you are inside the house, you can find and select Search the Cellar quest. Follow the quest guidelines to reach the bottom of the area, below the Blighted Village, to find Phase Spider Matriarch in BG3.
Phase Spider Matriarch stats and weaknesses
Phase Spider Matriarch has 15 Armor Class and 125 health. She can see in the dark and can cover large distances to attack you and your party. With 19 strength, 16 dexterity and +2 proficiency bonus, Phase Spider Matriarch is a well-rounded boss fight in BG3.
I have learned the hard way that Phase Spider Matriarch is immune to poison and takes normal damage against all other attacks. She is not weak against any damage, so we really don’t recommend focusing on a special skill or magic against her.
How to defeat Phase Spider Matriarch in BG3
Phase Spider Matriarch is usually patrolling her nest in BG3. Use stealth to get around the area and jump across the webbed bridges to reach her eggs. There are three sets of eggs present in the cave. Destroy all the eggs (with a ranged weapon) before you engage Phase Spider Matriarch as she will use them to hatch Phase Spider babies. One set of eggs is below the platform. Use the vines to climb down.

Once you have taken care of all the eggs, initiate the battle. Phase Spider Matriarch in BG3 is accompanied by two other Phase Spiders. We recommend taking down these spiders on an urgent basis and try to brace her attacks in the meantime.
Phase 1
Recommended party for this fight includes Gale, Lae’zel and Shadowheart. Having Astarion is a bonus at this point as he can solely handle this fight with ease. Once both phase spiders are down, turn your attention toward the Phase Spider Matriarch. Make sure to cast armor and magic buffs on your party members. Use pillars at the bottom of the arena to avoid direct contact.
After a lot of tries and deaths, I have found out that ranged attacks work best against Phase Spider Matriarch in BG3. They give you breathing room and allow you to heal. You can also burn the bridges of the web to slow her down a bit. Once everything is in place, use some debuffs on her and try to attack her from behind to frighten her.
Phase 2
Now use all the powerful attacks in your party and go to town on her. If you manage to do all of that successfully, Phase Spider Matriarch will end up losing half of her health in no time. Once at 50% HP, she will become angry. This allows her to sacrifice 1 AC point in favor of gaining 2 strength points.
Phase Spider Matriarch attacks will now hurt a lot more in BG3. Make sure that you don’t lose any HP during the first phase. The next phase is a battle of endurance. Rinse and repeat the strategy from the first phase. As you have already taken care of all the eggs and her underlings already, she is the only one you need to worry about right now.
Phase Spider Matriarch rewards in BG3

Once the Phase Spider Matriarch is dead, you can loot her body to obtain Poisoner’s Robe (10AC). This armor allows its wearer to deal an additional 1d4 poison damage with each spell (poison only).
This is everything you need to defeat Phase Spider Matriarch in BG3.