The Nonexistent Knight is a magical realist story set in the age of chivalry. As the end of Charlemagne’s reign approaches, however, the old chivalric ideals have begun to fade away. Amid this background, a set of armor has found a place among the paladins. Agilulf’s existence represents the dying days of the age of chivalry. His armor symbolizes the ideals which have been lost, and these ideals are powerful enough to give Agilulf something resembling life. The armor suggests the era of chivalry has become like Agilulf’s armor: an empty set of ideals, given life by the nostalgia for the past.

Agilulf may not exist, but he occupies a physical space in the world. He can swing a sword and issue instructions. In doing so, he functions as one of the most effective and diligent knights in Charlemagne’s army. He has overcome his own inexistence to achieve a great deal of glory. The other knights’ honor, their responsibility, and their adherence to the systems of manners and etiquette are shown to be as hollow as Agilulf’s armor. The empty suit of armor can outperform them. The other knights have their failings emphasized by the empty suit.

At the end of the novel, Agilulf feels too ashamed to continue.