Here's why:
* Story Focus: The story of Mystery Dungeon games revolves around the hero's journey and their growth, not necessarily physical evolution.
* Gameplay Balance: Allowing your hero to evolve could make the game too easy, especially in later stages.
* Uniqueness: The hero character is designed to be a unique and memorable part of the game, and evolution might change that.
However, there are some exceptions:
* Super Mystery Dungeon: In this game, you can choose to evolve your hero after reaching a certain point in the story. However, this evolution is a special form rather than a traditional evolution, and it doesn't permanently change the hero's appearance.
* Spin-offs: In some spin-off Mystery Dungeon games, such as "Pokémon Mystery Dungeon: Red Rescue Team" and "Blue Rescue Team," your hero's appearance changes based on their chosen job, but this isn't considered an evolution.
The bottom line is, in most Mystery Dungeon games, your hero will stay the same throughout the entire adventure. This is part of what makes the games unique and engaging, focusing on your journey and growth as a Pokemon rather than physical transformations.