M. A. Carrick

M. A. Carrick is two writers: Marie Brennan and Alyc Helms, who had each published under their own names and built the world of the Rook and Rose trilogy together over several years. The Mask of Mirrors puts a con artist into a noble family in a Venetian city where the card deck is a working system of magic and the criminal underworld has its own masked judge. Both authors trained in anthropology or folklore, and the invented card system holds together well enough that readers have made physical decks of it.