I never felt that my Avatar was picked
so well in my life. xD
There is much i would like to say to all that was spoken here today ... but i think i have better idea!
Lets get back on track ... shall we?
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1. Let her leave the camp (and find a way to get the artefact to the player), or
Just a small clarification ...
There allready is a way to get the artefact to the player ... and according to my testing, its implemented and working ... a bit wacky, i admit that, but acceptable.

I feel like the question being asked in this thread is:
---Is there a way for me to invite Shadowheart into the party and then get her to leave the party (and the campsite) *without* me personally initiating combat with her?---
Yes, exactly.

Its more a rhetorical question, since my goal is to achieve this no matter if it is there or not, so it can freely evolve from question to suggestion ... still, if anyone would know any way, i would like to know.

So far the only usefull advice was from neprostoman, who shared an idea to smash her head until she get pissed and leave by herself ...
She is alive ... and not in my camp ... so it kinda does work.
But its not ideal.
On the other hand tho it certainly prooves that she
can leave.
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If I'm reading this whole conversation correctly, the issue is that the game offers you the option to make Shadowheart leave, she agrees to do so but then proceeds to remain in your camp anyway.
Well ... maybe i should have screenshot it. :-/
But i believe you basicaly tell her that you dont want to "travel with you anymore" ...
My problem is that english is not my first, nor second, and basicaly not even third language ... so im not quite sure if her sitting in camp, dont "technically" fulfill that sentence.
In other words ...
What makes me started this topic is that i am a little affraid that this outcome is intentional. :-/
It's clearly either a bug, an oversight or an Early Access thing
I certainly hope so.
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we need to wait and see if the kick-out-of-party/camp-through-dialogue option is present in the full release. Arguing anything else in EA is purely academic, imo.
I believed that much should be obvious without saying.

Seems like i was wrong tho.
"Are you sure you want me to leave?" "Y/N,"
Its kinda sad/funny we have this for sending our companions to camp ...
But as their Dark Secret is revealed, they (to my knowledge) dont fight (metaphoricaly) to stay with us at all ... i just said Astarion to leave, and he left ... no questions asked, no futher dialogue, just an ingame popup window stating that he left my group permanently.
Its kinda depresing when i think about it.
such as the companion asking if there was anything that sparked the decision based on unlocked plot points for the character. What would take it to a whole new level beyond even that is if they could try to negotiate for you to change your mind.
I love this idea!