The fifteenth century chronicler Monstrelet indicated his suspicion of the motives of Gilles trial, noting, "The greater part of the nobles of Brittany, more especially his own kindred, were in utmost grief and confusion at his disgraceful death. Before this event, he was much renowned as a most valiant knight at arms". The Duke of Brittany was so certain of the verdict that he disposed of his own share of Gilles' lands fifteen days before the trial began.

Anthropologist Margaret Murray and occultist Aleister Crowley are among those who have questioned the traditional account relayed to us by the ecclesiastic and secular authorities involved in the case. Murray, in her book The Witch-Cult of Western Europe (pp. 173-74), surmised that Rais was a witch and follower of a fertility cult centered around the pagan goddess Diana. According to Murray, "Gilles de Rais was tried and executed as a witch and, in the same way, much that is mysterious in this trial can also be explained by the Dianic Cult."

According to Thomas Mann, de Rais embodied "the religious greatness of the damned; genius as disease, disease as genius, the type of the afflicted and possessed, where saint and criminal become one."

Rais's profile and notoriety has intrigued and inspired many other modern French thinkers and authors, such as Michel Tournier, Pierre Klossowski and Georges Bataille.

The best book inspired from Gilles’ case is the French decadent novel Là-bas ("Down There") by J.K. Huysmans.

• Bataille, Georges. The Trial of Gilles de Rais Amok Books. ISBN 978-1-878923-02-8
• Benedetti, Jean. Gilles de Rais. Stein and Day. ISBN 978-0-8128-1450
• Bordonove, Georges. Gilles de Rais. Pygmalion. ISBN 978-2-85704-694-3
• Cebrián, Juan Antonio. El Mariscal de las Tinieblas. La Verdadera Historia de Barba Azul. Temas de Hoy. ISBN 978-84-8460-497-6 (Spanish)
• Huysmans, Joris K. La Bas (Down There). Dover. ISBN 978-0-486-22837-2
• Hyatte, Reginald. Laughter for the Devil: The Trials of Gilles De Rais, Companion-In-Arms of Joan of Arc (1440). Fairleigh Dickinson Univ Press. ISBN 978-0-8386-3190-4
• Morgan, Val. The Legend of Gilles De Rais (1404-1440) in the Writings of Huysmans, Bataille, Plancon and Tournier (Studies in French Civilization, 29) Edwin Mellen Press. ISBN 978-0-7734-6619-7
• Nye, Robert. The Life and Death of My Lord, Gilles de Rais. Time Warner Books. ISBN 978-0-349-10250-4
• Wolf, Leonard. Bluebeard: The Life and Times of Gilles De Rais. Potter. ISBN 978-0-517-54061-9