Here's why:
* Fantasy: It features magic systems, mythical creatures, and a world with unique rules and cultures. The core premise of Allomancy (metal-based magic) is firmly rooted in fantasy.
* Adventure: The story follows a group of characters on a quest to overthrow a tyrannical empire, filled with action, intrigue, and exciting battles.
* Steampunk: The setting has a combination of advanced technology (especially the use of metal and machinery) with a Victorian aesthetic. This blend creates a unique steampunk vibe.
* Action: The books are packed with intense fight scenes, daring heists, and thrilling chase sequences.
So while "fantasy" is the primary genre, the Mistborn trilogy blends multiple genres to create a unique and engaging reading experience.