If putting the tadpoles into your brain, with all it's possible negative side-effects, isn't addressed really early in game through a npc/book/cinematic, this is a horrible decision. Just from the ui look alone, with it's black tendrils covering your brain, it feels like this will have big ramifications and the incentive to go "bad" with these extreme good bonus abilities is massive. The vast vast majority of players will have ONE play through not multiple to see different outcomes of bad/good/neutral play-styles. This might ruin the games overall experience for a lot of players if there isn't a counter incentive for the tadpoles in your brain or a huge red letter warning. Furthermore an dialogue option 30 minutes before the games ending to make it all undone and just remove the brainmaggots without any consequences would be the worst path this could take.
What if the counterplay of the tadpole powers is having friends? I know it sounds cheesy as hell but in PFH Larian said something about being able to gather many allies in a way or another and a power hungry monster might not have some helps or gifts along the game.
