I give you the write-up on mind-flayers:
Mind flayers, also known as illithids, meaning "mind flayers" or "mind rulers" in Undercommon, and sometimes referred to as ghaik by the githyanki, were evil and sadistic aberrations, feared by sentient creatures on many worlds across the multiverse due to their powerful innate psionic abilities.Dwellers of deep Underdark areas, these alien humanoid-looking beings sought to expand their dominion over all other creatures, controlling their minds to use them as hopeless slaves and devouring their brains for sustenance.
Not creatures to invite to adventure with. And please don't suggest they be romanced.
I was referring to the non-aggressive illithid that is available in the "Extracting the Parasite" quest in one of the options. There are also mentions in the lore of rare Ilythids who retained memories of life before the transformation, and are enemies of the rest of the Ilythids. Such rare cases may well be of a neutral alignment. Perhaps even regret that they have become so. And one of them may have their own motives to help our heroes