Rereading the Library of Souls, I was confused by a couple of things
At the beginning, when Emma, Jacob and Addison were on the train after escaping from the wights, they had a dialogue about Claire and Fiona. Addison mentions gas, which is disgusting to the peculiars (as far as I remember). Emma is outraged, because wights promised not to use it anymore. I don't understand why she's outraged, because wights did a lot of shitty things, and an unfulfilled promise is everything
The second moment is already at the end, during the 1st battle of the Devil's Acre. While they were fighting, Bronwyn says that they must continue, because wights will still be chasing them. Wight in the pit talks about signing a contract, and Miss P replies that they signed one once, and it wasn't even worth the toilet paper it was written on
That is, they also drew up some kind of contract with them. Given the first point, he may have been touching the gas.
Considering all this, are you saying that the Ymbryns signed a contract with wights, the ones who made some kind of gas, killed the peculiars, destroyed the loops, and did a lot more? What were they trying to achieve with this piece of paper? What will they stop? It's kind of doubtful.
