While there are other antagonists in the movie, like the Bettermans, who represent a different way of life, Grug's biggest enemy is his own fear of change and the unknown. This fear keeps him trapped in his cave and prevents him from embracing the new world and all its possibilities.
Here's why Grug's fear is considered the true villain:
* He drives the plot: Grug's fear is the catalyst for the family's journey and the source of many conflicts.
* He hinders progress: Grug's fear prevents the Croods from adapting and evolving, leaving them behind in a changing world.
* He represents a universal struggle: The fear of the unknown is something everyone can relate to, making Grug's struggle particularly relevant.
While the Bettermans act as antagonists, they are primarily driven by their own need for dominance and control. Grug's fear, however, is a more internal and personal struggle, making it a more profound and impactful villain.