Ok so this stuff is even
more complicated: "The deeper you go through the illithid skill tree, the more powers you'll discover. But nothing comes without cost. While your companions can also consume parasites to gain their powers, not everyone in your party will agree to it, and your companions' perception of you can undergo a significant shift based on how you approach this opportunity."
Its nice when the super evil power in a game actually has a cost
It's unclear how much of a cost there is...it sounds like they object if you try to put more tadpoles in them but if you use them all on yourself they might not be the wiser, and I don't think I am inclined to spread them around...though they also say it's more complicated than that...so it sounds like there's possibility there to shift the way they see you...in a way you control. Probably skill checks involved there and dice rolls but it might not be as simple as they just leave either. My evil character would probably try to mind control his companions should the opportunity arise and they do say one part of the tadpole tree is about affecting dice rolls in conversation and control.
This is also a game where you can also win at evil, which is really nice.