Warg dung? What’s this? I snuck my way in and ended up slaughtering all of the goblins, so I never found out the prerequisites for entering the camp normally.
Sorry for the spoiler, I didn't think it was that major as its just one of the ways to get in ...
Without using the tadpole or fighting, you have to pass a skill roll then smear warg dung over your face as warpaint to get in.