Shrek is a surprisingly dark film at points, fully leaning into its status as a sardonic answer to the typical fairy-tale-inspired storytelling produced by studios like Disney Animation. But there may be more dark layers in the series than anyone ever truly realized, including one that turns one of its main players into a full-fledged cannibal.
At the onset of Shrek, Princess Fiona has been trapped in a tower for years. The film's plot eventually reveals the princess was cursed with a spell that transformed her into an ogre every night. Separated from the world, Fiona awaited her rescue by her "true love" -- intended to be the Fairy Godmother's son, Prince Charming, as revealed in Shrek 2. However, the unexpected intervention of Shrek resulted in her premature release before Prince Charming could find her. Eventually, Fiona and Shrek's emerging love broke the curse in a unique fashion -- turning her fully into an ogre who could then spend the rest of her life with Shrek.
But since the film's release, a plot hole in her imprisonment has intrigued fans -- if Fiona was trapped in the simple tower for years, how did she survive? There's no easy access to food, and the treacherous location makes it unlikely anyone could regularly bring supplies to her -- let alone get past the dragon to feed her. Well, a gruesome theory from Reddit user Froidster offers a particularly dark take on the concept, suggesting that Fiona has been surviving on the flesh of the knights who have fallen in their mission to rescue her from the dragon that guards the castle.
It's established early in Shrek that many knights had tried -- and failed -- to rescue Fiona. Throughout his own visit, Shrek even finds evidence first-hand of the knights who've died in their attempts, finding skeletons and left behind armor. The dragon is also shown eating people whole no problem, as it eventually does to Lord Farquad, explaining the general lack of corpses. However, within the castle is a cauldron and a cookbook titled "Knightly Treats," which may tease a fate worse than death for the knights.
The theory suggests that the dragon, as part of her duty to mind Fiona, cooks some of the knights she captures and feeds them to Fiona for sustenance. This would explain how Fiona survives for years in the castle with no other apparent source of sustenance, as she was always intended to one day be rescued from the castle, requiring her survival. The abandoned skeletons of the horses left behind by the knights outside of the castle imply she isn't being fed those animals, leaving the human knights as likely her only real possible food source.
It's even possible that Fiona only eats the men while in her ogre form, which would make sense, as the ogres of this universe are seen treating various body parts like eyes as something of a delicacy. But due to occasionally human nature, this would likely still classify her as a cannibal. It could even help justify her general cavalier attitude to danger later in the film, as she's already seen -- and experienced -- some very dark things. It's a dark theory, but not one that's out of place with other similar dark readings of the material. Shrek was always a subversive and dark take on traditional fantasy tropes, so having the delicate princess also very familiar with the taste of human flesh would make a certain amount of sense.