Ok, now I understand the positive effect, but most of the dice rolls will be for something good for us/me - so if the heal check, the swim check, make the knot check and all of them can result in a bleeding ...
I'm not sure if this is group compatible. I erase it, too bad.
I wrote in my character sheet, Cassiopeia comes from 'Deep Dark of the Wisla cavern lake'. I thought about a normal big cavern, mostly filled with water, two or three hives of ohpidians living in it. Land-dwellers don't have much to stand on and most of the explorers, hunters and fishers never came back. The Larata Swamps sound like a good place for that.
Between the meeting of the ophidians and the start of the adventure there should have been some time (to loose the rest of them and learn a language).