There’s plenty to discover when you reach Rivington in Act 3 of Baldur’s Gate 3, and one of the town’s most innocuous landmarks holds one of its darkest secrets.
Rivington’s windmill is a decrepit looking building just a little east of The Rivington General. It’s easy to move right past when you first encounter it, especially because the door is locked, but if you force your way inside you’ll find a hatch leading to a dusty basement. Laying on the floor is a sleeping mind flayer.
The moment you see the mind flayer, the Emperor reaches out telepathically to urge you to kill it. Taking his advice gives you a leg-up in the fight, but since you’re likely facing the mind flayer with your entire party, this isn’t a particularly difficult encounter no matter what you do. There are two notable pieces of loot that you can get from killing the mind flayer: a brain that can be used to gain a point for your Illithid powers, and a Ring of Truthfulness that gives advantage on Insight checks to its wearer.
These are actually the best rewards you can get from this particular encounter, so I’d recommend killing the mind flayer immediately. If you aren’t so violently inclined, you can talk to the mind flayer and listen to its unsettling request.
Meal procurement
The mind flayer explains that it only just recently gained its full Illithid body, and it needs to eat. It asks you to bring it a fresh corpse. In reality, any corpse will do. You can kill the first townsperson you see, or find someone who died by other causes. Either way, pick up the body and bring it back to the mind flayer. It’ll thank you by giving you another point for your Illithid powers before heading out into the world.
On the other hand, when the mind flayer makes its request, you can pass a DC 15 Persuasion check to convince it to find a meal itself. When you pass, the mind flayer leaves, and you finish this quest without gaining any rewards.
Unless you’re doing an evil playthrough and trying to help the Absolute gain as much power as possible, there really is no upshot to letting the mind flayer live. You get the best rewards from killing it, and considering this is likely going to be a four-on-one fight, you can scoop up your loot without having to tax your resources that much.
