[4] An e-book edition was published by Gollancz's SF Gateway imprint on September 29, 2011 as part of a general release of de Camp's works in electronic form.

Returning to his home plane early and with extra iron, he resolves never again to leave the comforts of the Twelfth Plane — until he realizes how dull it is compared with the picturesque insanity of the human realm... By internal chronology, The Fallible Fiend is the second story in the Novarian series, coming after the short story "The Emperor's Fan", which is set centuries before the others, and prior to the Reluctant King trilogy.

(The Paaluan invasion of Ir is mentioned in the second and third books of the trilogy, The Clocks of Iraz and The Unbeheaded King, respectively, as an event occurring either recently or some generations past.)

"[7] Roger C. Schlobin praises the book's "[d]elightful episodes occur[ring] as the fiend misunderstands his commands and tries to function in a totally alien environment, which is, of course, quite normal for the reader."

[8] Brian M. Stableford calls "The Fallible Fiend ... more offbeat than de Camp's other ventures in the genre," and Zdim "perhaps the only sword-and-sorcery hero who regularly devours people.

The hero's contact with other cultures, the "fantasy staples" of "the semi-human Zaperazh, the horse nomadic Hruntings, and the cannibalistic Paaluans ... clearly shows why each is as implausible as the more 'corrupt' human institutions of civilizations.

"[10] Don D'Ammassa finds "The Fallible Fiend ... in much the same vein" as The Reluctant King series, with "[m]ost of the humor com[ing] from the efforts by the demon to understand human behavior.