Producers considered hiding the credit for series screenwriter Gen Urobuchi as red herring to audiences regarding the true nature of the show, however the plan was foiled due to a premature staff leak. Urobuchi is noted for writing dark stories.
Gen Urobuchi compares Kyubey to be like H.P. Lovecraft's creatures, in that they are uninterested in humans feelings.
The text and writings of Johann Wolfgang von Goethe 's "Faust" a well known story in which a man sells his soul to the devil, can be seen scattered through the series usually in the "witch runes."
Puella Magi was supposed to be Latin for "Magical Girl". However, if that was the intended translation, then "Puella Magi" is a mistranslation, and should have been either "Puella Maga" or "Puella Magica". As-is, "Puella Magi" translates to "Girl of the wise man".
Emiri Kato particularly enjoys the magical girl genre of anime and felt great distress when she learned of the nature of her character Kyubey and the series.