https://catalog.hathitrust.org/Record/009478353320 page novel abt a bored lord who joins a fencing club where all its male members wear masks, and they are judged by a masked woman in their DUELS TO THE DEATH
This is Limited (Search Only) view for me; does it work in the USA? The Twitter user did post a direct-to-PDF link as well:
https://nyc3.digitaloceanspaces.com/sffaudio-usa/usa-pdfs/TheWomanOfDeathByGuyBoothby1900.pdf
Wikipedia article: https://en.wikipedia.org/wiki/The_Woman_of_Death
EDIT: It's on Google Books: https://books.google.ca/books?id=3KFCAQAAIAAJ