Baldur's Gate 3 Strong Disc Guide - Entering the Underdark through the Defiled Temple
Baldur's Gate 3's world is gigantic, and a major aspect of it all is the treacherous Underdark; there's numerous methods to descending to its depths, but one of the safest methods to get a foothold early on is by discovering the hidden entrance to the underground Selunite Outpost. Not only does it immediately give you access to a fast-travel waypoint, but you won't immediately be thrust into an encounter of some sort. The question is; how do you reach it?
Finding the Strong Disc Puzzle in the Defiled Temple
To enter the Defiled Temple, you'll need to either lockpick the door, steal or loot off the corpse of Priestess Gut, or either willingly - or unwillingly - go along with her plan to brand you. Either way, once you've unlocked the door (and dealt with Gut and her Ogre bodyguard), you'll be able to find a room with a peculiar set of patterns on the ground. With a grand total of 4 discs on the ground, your goal will be to get all of the black dots within the disc highlighted by the sun through the ceiling.
Chances are you might have noticed a hint for this solution elsewhere within the Goblin's encampment, as shone below; during the Early Access period of the game, unlocking the path to the Underdark was complicated by the inclusion of dots that were half black and half white; thankfully, things are considerably more straightforward with the release version.
Once you've completed the puzzle, you'll hear shuffling near the back of the room, and the path down to the Underdark will appear.
How to skip the Strong Disc Puzzle in the Defiled Temple
Does the above puzzle seem too tough for you? Thankfully, if you can manage to succeed with a Perception check, you won't have to engage with it at all; if one of your party member succeeds the check near the collapsed statue near the back of the room, you'll be able to interact with a lever that will accomplish the same task of unlocking the path forward.
Regardless of whether you complete the puzzle the intended route, or by discovering the failsafe switch, congrats on reaching the Underdark! At the bottom of the ladder you'll find the Underdark - Selunite Outpost waypoint, meaning that you'll be free to explore to your hearts content without any worry about having to find your way back later. Venture forth to the next part of your adventure!