However, there is a character named Berry Master Kent in Pokémon Emerald. He is a strong Trainer who specializes in using Pokémon with high Berry Power abilities. While he doesn't exist in FireRed, he serves as a notable example of a berry-themed trainer in the Pokémon world.
If you're looking for a character in FireRed who is particularly knowledgeable about berries, the Berry Keeper in the Berry Forest is a good choice. He gives you tips on how to grow and cultivate berries.
Overall, while FireRed doesn't feature a dedicated "Berry Master," it does offer opportunities to learn about berries and their uses through various characters and gameplay elements.