Here's why:
* Magic System: Eragon features a well-defined magic system based on ancient languages and the use of dragons, which is a core element of fantasy.
* Medieval Setting: The story takes place in a medieval-inspired world with kingdoms, knights, and a strong emphasis on tradition and folklore.
* Supernatural Elements: The presence of dragons, elves, dwarves, and other mythical creatures clearly places the story in the realm of fantasy.
While Eragon does include some elements of adventure and action, which are common in both fantasy and science fiction, the overall focus on magic, mythology, and a medieval setting firmly categorizes it as a fantasy novel.