A lot of games have quests that tie into others and lock you out of completing them until all their prerequisites are met. Baldur’s Gate 3 is no exception, with some moments seeing several quests complete at the same time.
Before you can complete this quest, you will have to have already completed two others: Get Orin’s Netherstone and Get Gortash’s Netherstone. These are story-centric quests that will need to be completed in order to finish the game.
How To Reach The Morphic Pool
Start by traveling to the Basilisk Gate Waypoint in Lower City. Once you arrive, follow along the wall on the west side. You will walk around the building and will come to a sewer hole in the ground. You can use this sewer hole to gain access to the city’s sewer system. You will now want to travel to the Undercity Ruins using these sewers. Navigating them can be a little complicated, but thanks to having coordinates on your map, it is a lot faster to just head to those numbers than reading a long list of when to make turns and what markers to look out for.
Make your way from where you entered the sewers to X: 140 Y: 940. This is where you will find the Waypoint. To the east of the Undercity Ruins Waypoint, you will see a very large door frame. Head on through this frame. Take a left turn and head down the descending trail. This trail will lead to a large stone pillar that has been knocked over. Keep heading lower and lower, and you will reach the Temple of Bhaal. There is another Waypoint here; be sure to activate it. Head towards X: -3, Y: 1000 to find a set of large doors.
North of this temple will be the Morphic Pool Dock. You can find it at X: 80, Y:1150. You will see a small wooden dock, and at this dock, a small wooden boat. Interact with the boat to begin rowing. The boat won’t make the journey, but your party will safely be able to get to the other side and will sense the presence of the Elder Brain. You will now be in the Morphic Pool location.
How To Reach The Elder Brain
The path you are now on is quite linear with no branching options. Follow the path, and you will come to a very shoddy-looking bridge. You will need to cross this bridge, but you may notice that there are intellect devourers on the other side. Do not worry or waste any of your spells preparing for a battle; they will flee provided you don’t attack them from a distance. Click where you see them gathered and follow them with the camera as they flee.
They will lead you straight to some green pools. If you did lose track of them, these pools are at X: -35, Y:3735. Here is where the fight with them will take place. Dispatch these foes and head east where you will encounter a broken bridge. Jump the gap and continue to head east. You will find a locked door that you will want to take a left at.
Behind the locked door will be a corpse you can loot. It has 1 gold, 1 malachite, and 1 potion of healing on it.
Ahead of this path will be a lengthy exchange of dialog, filled with rolls to be made. Be sure to make a save at this point as it will all come down to how well you roll. Continue on the beaten path and your party will make Saving Throws against their minds being broken by the Elder Brain. The screen will shake, and you will see lots of pulses on the screen when this happens. You will arrive at a large green pool. This will trigger a cutscene where you will see the Elder Brain slowly rise up from the pool. This will begin the dialog exchange.
How To Free Orpheus
You will get plenty of options for your rolls, so it is best to just use the options that will give you the highest results. If your character is a Fighter with high Strength above all else, choose to Dominate The Brain with your Strength Ability. On the other hand, if you have invested heavily in Intelligence for a Wizard, choose to Dominate The Brain using your Intelligence Ability instead. Once all the rolls have been made, the Elder Brain will rise from the depths and make its way to the surface. It will tower over the city in a dramatic cutscene.
You now have a dialog exchange with The Emperor, informing you that the Elder Brain has evolved into something far worse than before. You don’t have to worry about any rolls to get a favorable outcome for this dialog exchange. Once the dialog is over, you will find yourself in a twisted and surreal environment.
Follow The Emperor, and he will lead you Orpheus. Orpheus will be inside a sphere with two red stones on either side. Shattering these stones will free Orpheus.
After some dialog to push the story plot, the quest will be marked as completed. Depending on your choices, one of you will become an Illithid.