James Branch Cabell
Cabell is now forgotten by most people but his work affected later writers of fantasy fiction. Robert Heinlein's Job, A comedy of Justice has an appearance of the Slavic god Koschei (from Jurgen). Fritz Leiber's Swords of Lankhmar was also affected by Jurgen. Jack Vance's Dying Earth books show a similar style to Cabell's writing. Cugel the Clever in those books is very similar to Jurgen.