The Baldur's Gate 3 Sarin skeleton puzzle is one you find while roaming the sewers and cisterns of the city proper in Act 3. In the centre of the underground region, you'll encounter Aelis Siryasius and his army of grease creatures. The sewer entrance on the western end of the Lower City, just south of the gate to the Upper City, will deposit you near Aelis' location, and a conversation with the sorcerer will trigger if you try and cross the bridge to his location. This kookster is on the run from Absolute cultists, and if you can't convince him you're friendly, you'll be fighting for your life against his fatty monsters.
Whether you convince him or not, you'll discover that he's protecting the corpse of his dearly departed comrade, Sarin. If you walk over and inspect the skeleton you might notice that it's missing a skull, and when you activate it, a slot appears into which you can insert an item. So, here's how to solve the Baldur's Gate 3 Sarin skeleton puzzle and find her missing head.
