Not taking your favorite cleric of Shar to a shar themed (and named) dungeon is on you anyway...
Maybe ... but thats not the point here, is it?
Oh, and if you pay attention to what she says to you, the artifact has a mind of his own and decides who it will stay with.
Wich makes perfect sense, as long as you are traveling together ... bcs the only thing that is changing, is who is holding it as you travel, wich makes no difference.
BUT!!!
When she decide to leave you, she imediately abandon her most holy and "will defend it with my life" quest ... bcs you simply pissed her off.
I get that she is angry ...
I get that she dont want to travel with us anymore ...
What i dont get is that she just leave with no even mention.
I mean, it was brought up abowe ... what Shadowheart basicaly do is:
"You dont care about my feelings enough, and so i will leave you now ... i allso will horribly, painfully, and instantly turn into Mind Flayer, while i completely abandon the only reason i was here in the first place, and let you keep the only thing that is protecting you, wich was mine!
That will teach you!"
In what universe that would make any sense? O_o
