Baldur's Gate 3 starts off with a body horror bang as the Mindflayer puts a little tadpole with teeth in through your eye. As you begin your adventure to get off his failing ship, you'll hear a little voice calling for you. Instead of finding a helpless person needing rescuing, you find a man strapped to a chair with his scalp removed and his brain pulsing ominously. As Baldur's Gate 3 is an RPG, there's a choice to be made here: remove and save the brain, leave it in the man's head or destroy it, so let's look at what the best decision is.
Should you save the brain in Baldur's Gate 3?
The short answer is yes, you should save the brain, and here's why.
The brain speaks telepathically with you, informing you that it is now under the control of the Mindflayer and that you should definitely free it from its prison, i.e., this poor gent who is about to literally lose his mind. You can either help the brain, walk away from the scenario altogether or destroy it. The brain will call itself Us and refer to you Friend, so there's one reason to keep it alive.
If you have Perception or Arcana skills, you will passively roll to get some unique dialogue, and after that, you can choose whether to destroy, leave or save the brain. If you choose to save it, you need to remove it using abilities: Medicine, Strength or Dexterity. For these, you'll be manually rolling the dice, so choosing one where you have bonus points is a smart choice. I went with Dexterity and got a successful roll, meaning I prised it gently from the skull. There's also an Investigation roll which gives you a little bonus information.
If you roll successfully on either three options, you'll whip the brain out. If you fail the roll, you can always load back and try again, or be faced with either destroying or leaving it. If you destroy it, you'll squash it with no chance to fail. Leaving it in the body ends the quest and Us won't join your party.
What should you do once you remove the brain?
If you are successful in removing the brain, there is another option: mutilate it to cripple it should it become hostile. Honestly, this is not worth doing, because Us sprouts some legs and claws and joins your party once freed, and having a debuffed party member is not good. You can build a party quite quickly in Baldur's Gate 3 and Us has plenty of hit points, making it a pretty hardy and handy member of your team, if a little weird. If you do want to injure it, you'll need a successful Dexterity roll. You can also choose to kill it even if you decide to free it and not injure it.