Apart from Horacio and La Maga, the other members of the Serpent Club include Ossip Gregorovius, who is presented as a rival for Lucía's affections, the artists Perico Romero and Etienne, Etienne's friend Guy Monod, Wong, and Ronald and Babs (who are married).
Other major characters include Pola, another Parisian love interest of Horacio's, who is diagnosed with breast cancer after being cursed by La Maga; Gekrepten, Horacio's lover in Argentina; and Morelli, an Italian writer much discussed by the Serpent Club.