Baldur's Gate 3 is all about choices — well, that and exploring a fantasy world full of unique creatures and people. From how you interact with an NPC vendor in a small town to deciding what to do with an enemy recently bested in combat, you will have to make a lot of decisions as you work your way through the expansive story of the game.
One of the first decisions that will be presented to you in the game is what to do with the Mindflayer Tadpole implanted in your brain in the opening cutscene. You will have a lot of different options to take the parasite out of your skull, and one of those comes in the forms of Raphael, a Tiefling who says he can cure you as long as you give him something in return.
Should You Trust Raphael?
In exchange for curing you of your skull-based illness, Raphael will ask you to retrieve the crown that controls the Elder Brain. This crown is going to give him a lot of power. Which begs the question: should accept his deal to rid yourself of the parasite, or find another way?
The best answer is: no. Do not accept the deal with Raphael. Of course, if you are going for a more sinister character, then the deal may be enticing to you. However, for the most part, the deal is a bad one to take.
Raphael is clearly up to no good, and his behavior is nothing if not suspicious. Your party members will even call this out and encourage you to not trust Raphael in his request. Even more, the Narrator will straight up tell you that Raphael is clearly aiming for something evil and that the deal with him is not worth the pain it will cause.
Besides, the demon that you will have to take down to get the crown is a real pain to deal with. Save yourself some time and refuse his deal to make your playthrough a lot better.
Raphael may not be happy, but refusing the deal will still present you with plenty of options to get the parasite out of your brain without having to make a deal with a literal devil. And even with the Elder Brain not being a great entity to have alive, you will still be able to take it down later through different means.
With all of this considered, the deal just isn't worth it, and you should dedicate your time to finding a better way to help your character cure themselves. Now, this does bring up an entirely different path: take the deal from Raphael but do not follow through on your end of the bargain.
You can sign the contract and reap the immediate rewards that are given to you, such as being given the Orphic Hammer by Raphael, which is a pretty solid weapon to have in your possession. And then, later on, when you are having the conversation at Sharess' Caress, you can go back on your word and keep the hammer. This may not make Raphael the most happy, and it certainly may have members of your party disapprove initally, but it is another path to take.