[Keystones &etc]
It's hard to tell who knows what at this point. So for the sake of making sure everyone understands what we're doing:
Each Judge has a keystone and as far as we can tell, it's their one exploitable weakness. With a Judge's keystone in our possession, we can destroy them for real-- and now the Gentleman's presence means that this time, they'll actually die.
Our plan has been to collect as many as possible as quickly as possible so we can start making our move. We already have a few in our possession- Messenger's, Librarian's...Queen's... The rest we still need to locate. And we know that Blanks can sense them when they're close, as we discovered when we rescued Messenger's symbol.