I think Monica Belucci is listed as the lead character, so it seems pretty pointless to speculate. IMDB isn't even reporting that Keira is attached in any way shape or form. From what I understand, Joel Schumacher made a comment about wanting Keira in it, but then, pretty much everyone in Hollywood wants her bankability.
"Purgatory's kind of like the in-betweeny one. You weren't really shit, but you weren't all that great either. Like Tottenham."
I'll try being nicer...if you'll try being smarter.