[1] The Red Sphinx is a sequel to The Three Musketeers, written by Dumas but left incomplete after 75 chapters.
It is a sequel in story terms, but none of the Musketeers appear; the story chiefly follows Cardinal Richelieu, Queen Anne, and King Louis XIII, and a new hero, the Count of Moret (based on the real-life Antoine de Moret).
Fantasy novelist Steven Brust's Khaavren Romances books have all used Dumas novels (particularly the d'Artagnan Romances) as their chief inspiration, recasting the plots of those novels to fit within Brust's established world of Dragaera.
[4] His 2020 novel The Baron of Magister Valley follows suit, using The Count of Monte Cristo as a starting point.
[5][6] Sarah Hoyt's (nom de plume Sarah D'Almeida) Musketeers series[7] begins with Death of a Musketeer, a Mystery Book Club selection, and includes four other titles from Berkley Prime Crime[8] and Goldport Press.