A couple of details that I think I missed:
Towards the end of the session, everybody but Lucretia had realized, one way or another, that “Octavious” wasn’t really Octavious. Several had seen through Esmerelda’s glamour, while the rest had noticed oddities of behavior. The group even started taking advantage of her ability to change appearance. Finally, she broke down and dropped the charade, declaring herself to be a changeling.
She had been part of a fae travelling circus, she explained, when she finally got fed up with her own kind and fled. During her travels, she had bumped in to Octavious, who was leaving London to find either a cure for lycanthropy or a nice farm where he could chase rabbits all day. He had shown her a kindness and they traded stories. Between them, they had hatched a plan: she would take Octavious’ face and position, hiding out from her past while offering support to his friends and family. She would be able to support their monster hunting mission while also sparing them worry over his absence.
Everybody accepted this fairly readily, at least initially, aside from Lucretia. For some time, she refused to accept the story, declaring that this “Octavious” was the original and it was all some complex delusion. In the end, she seemed to “agree to disagree”, saying they would “make it work”.
Afterwards, Tommy Nine slipped out to send a telegram to his handlers, informing them that he had located a fae who claimed to be a rogue, and requesting further instructions. Later on, he received a return telegram, telling him to observe and report, but if it seemed that she was about to initiate some supernatural trouble, he should immediately kill her.