Anachronisms
Schmendrick uses judo to defend himself, the Talking Butterfly quotes Shakespeare and lines from popular commercials, and Prince Lír makes mention of a half-dozen tried-and-true fairy tale plot formulas. These oddly modern insertions and breaking of the fourth wall are deliberate attempts to both poke fun and a respectful tribute aimed at the fantasy genre and the novel is rife with these images.
Fantasy/Mythology
Despite the novel’s many jabs at the fantasy genre it is still is at its very core a fantasy novel; as such the author pulls from a vast menagerie of creatures from various mythologies. Many of the mythologies surrounding these creatures are used as plot drivers in the novel and are used to add overall color and flavor to the narrative.
Deconstructionist Approach
The Last Unicorn is not only homage to fantasy stories but also a satire of the genre. It breaks the fourth wall by featuring characters extremely familiar with well-known fairy tale plots and sometimes even having these characters break down plot elements point by point. This deconstructionist approach not only distances it from the rest of the genre but also forces the reader to reconsider previously held notions of the genre.
Isolation
Many of the characters in the novel experience or live out their lives in some form of isolation, either by virtue of being an immortal creature whose lifestyle and motivations are so alien--such as the titular Unicorn--or by being literally alone for years on end because of state of depression--such as King Haggard. Prince Lír, is also a lesson in isolation as he shares the castle with his emotionally distant father. Molly, likewise, lives an insural life. Despite being married she has no emotional connection to her husband and cares even less for his underlings.
