we can create a great looking bystander to other people's hero stories
I really hope that this is not the case. It was one of the major defects of DOS2 and they should have learnt better.
I haven't played the early access, so I don't know much, but I hope that Tav is already shaped like the dark urge. Maybe the other orogins will not have the same interaction with the illithing as Tav? I remember Tav dream of someone and you have to create it when you create Tav. Will the other origins dream this person too?
One can only hope.
I have not been using the tadpole and basically had only some class or background statement options in conversations, which also happens with the companions. Also as far as I understand it the tadpole is available to every character that is part of the playable group. So nothing about it would be limited to Tav.
