Don Quixote, a Spanish gentleman, transforms into a self-proclaimed knight-errant, driven by obsessive reading of medieval chivalric tales. Convinced he must revive chivalry, he dedicates himself to upholding justice and protecting the helpless. His distorted perception frequently misinterprets reality, leading him to see windmills as giants or a barber's basin as the legendary Mambrino's helmet. An unwavering commitment to his idealized duty fuels his quests.

His devotion centers on Dulcinea del Toboso, a peasant woman he envisions as his noble lady. Though she remains unaware and never appears, he frames all his adventures as efforts to honor and win her favor, making her the inspirational force behind his chivalry. This love exists purely in his imagination, highlighting his detachment from reality.

His squire, Sancho Panza, is a peasant laborer initially motivated by greed and promised rewards. Their journey fosters a complex bond, blending Sancho's exasperation with deepening loyalty. Sancho evolves from a skeptical follower into a devoted companion who sometimes offers pragmatic wisdom, contrasting his master's idealism.

Don Quixote's delusions manifest in frequent misadventures: attacking windmills believed to be giants or brewing imaginary elixirs like "Fierabras' balm" for its supposed healing powers. These episodes underscore his comic-tragic inability to distinguish fantasy from reality. He maintains persistent optimism and resilience, continually seeking to confront perceived injustices despite repeated failures and ridicule.

Antagonists include the Duke and Duchess, aristocratic figures who deceive and manipulate him for amusement. They fabricate elaborate fake quests and dangers, exploiting his delusions to humiliate him, yet their cruelty inadvertently reinforces his self-image as a knight facing genuine trials. Others, like the mischievous maid Altisidora, mock his romantic ideals through feigned affection.

Originally Alonso Quijano, a hidalgo from La Mancha, his immersion in chivalric romances leads to his breakdown and reinvention. He rides an aging horse, Rocinante, symbolizing his own worn-out yet steadfast nature. His fixation on knight-errantry isolates him from societal norms, positioning him as an absurd yet isolated figure striving for heroism.

His narrative emphasizes consistent idealism amid adversity. References imply his eventual return home, disillusionment, renunciation of his knightly identity, and death, though the anime adaptation does not elaborate on this conclusion. Throughout his journey, he maintains an unintentionally comedic yet honorable demeanor, embodying themes of misplaced nobility and enduring imagination.