I do not host anything, I just tried to expand her story upon general theme of this game of Personality VS Power, which Larians themselves forgot about in Act 3. It starts with Illithid abilities, usage of which shoud "take something of you". You surrender your sense of self and your higher need such as love, recognition and social links for more power to fuel your basic needs such as hunger and survival. You can refuse this power and remain what you are and stay true to your dreams OR you can surrender yourself and become something greater, an apex predator among intelligent speciec though forever chained to your bottomless urge to consume others mind and slowly lose yourself to this hunger. This is what being Illithid means.
(well, actually you do not transform into one, you just die and larvae takes over your body and memories. That's why the soul isn't there - it leaves the body with the death of a host, larvae just thinks of itself as the person it just ate because it starts its life with host's memories)
Astarion can ascend but complete lose himself, drunk in the sea of new possibilities and his cravings for domination. SH is already lost herself, you can help her recover. Laezel doesn't have a sense of self until she denies her supposed goddess, until then she bootlicks her society's hierarchy for a chance of recognition and power. Minthara lost herself in the cult and can be recovered, but her questline is even more barebones than Karlach's. Gale and Wyll are just 'sinners' that now reap what they saw, I dont see this theme in their story. But they still have much more agency in the events of the game than Karlach. What I'm saying is that Karlach doesn't gain any transformation of character, she doesn't evolve nor learns anything other than accepting her fate which is not a theme suitable for full fledged companion I think. I can be there, but there should be more for a character then, otherwise its bland.
