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.
Sarin's Skull location
To fix the skeleton you need to find the Sarin's Skull item—if you gaze into her coffin, you can quite clearly see that her head is missing. Make your way to the Undercity Ruins waypoint, which is directly to the north of where her skeleton is. Once you arrive, head west until you find Voiceless Penitent Bareki, then look for the pouch just up the stairs behind him to find Sarin's Skull. You'll likely have to sneak when stealing this so the vendor doesn't realise.
Now you've got the skull, you can go back to Sarin's coffin. If you managed to convince Aelis Siryasius not to attack you the first time, he will become hostile once you start messing around with Sarin's corpse. Remember, grease is flammable, so fire attacks are a good method to beat him quickly. If you prioritise killing him, the Grease Mephits he's summoned will also perish. I'd recommend fighting him from a distance with fire AoE attacks, rather than starting the fight right in the middle of that greasy hellhole.
When they're all beaten, simply activate Sarin's corpse, and slot in the skull to receive your reward: the Chancer's Carcanet. This gives you the ability to use a Reaction to make an Attack Roll or a Saving Throw with Advantage once per long rest.
Not the worst magical effect in the game, and there aren't a ton of great amulets in BG3, limiting its competition, but this quest was definitely more about the journey than the destination. The saving throw function is definitely the more noteworthy feature—at this point in Baldur's Gate 3, advantage on a single attack is nothing. In Act 2, the Risky Ring (advantage on all attacks, disadvantage on saves) and the Gloves of the Automaton (advantage on attacks for 10 rounds per Short Rest) trivialize the Chancer's Carcanet. With its saving throw advantage, the Chancer's Carcanet could be useful for fights like Raphael or the Wyrmway guardian, who have some nasty attacks that can be mitigated with saving throws, particularly on Honour Mode.
