Brian's transformation and maturation in the novel are quite remarkable. He starts as a rather immature character but grows through difficult situations and interactions with other characters. This leads to him becoming more self-aware, empathetic, and mature in his decision-making.
Scout matures a lot as the story progresses. She learns to see beyond surface-level differences and becomes more empathetic and understanding of others.
Jem matures by facing various challenges and learning from them. He becomes more understanding and empathetic.
Will Halloway undergoes significant growth and transformation. He starts as a somewhat naive and timid character but becomes braver and more self-assured as the story progresses.
Gulliver undergoes significant changes. He starts off naive and wide-eyed but becomes more cynical and disillusioned as he experiences different lands and their oddities.
Hyde undergoes significant changes. He starts as a mysterious and sinister figure but gradually becomes more exposed and desperate as the story progresses.
She undergoes significant character development. Her beliefs, values, and behaviors all shift as the story progresses.
Huck changes a lot. He starts out as a mischievous kid but grows more mature and empathetic as the story progresses.
Jem changes quite a bit in the novel. He goes from being innocent and somewhat oblivious to becoming more perceptive and sensitive to the injustices and complexities of life. His growth is driven by the challenges and experiences he faces.
Utterson undergoes significant changes. He starts as a reserved and skeptical character but gradually becomes more involved and determined as the story progresses.
Ponyboy undergoes significant transformation. At the beginning, he's kind of carefree and stubborn. But as the story progresses, he gains a deeper understanding of life and the people around him, and becomes more responsible and sensitive.