What great change did Matthias undergo during the story?

In the story, Matthias undergoes a significant transformation from a timid, inexperienced mouse to a courageous and skilled warrior. Initially unsure of his abilities, he gradually gains confidence through his experiences and the mentorship of others in Redwall. His determination to protect his home and friends ultimately leads him to embrace his role as a leader, showcasing his growth and resilience in the face of adversity. This journey not only strengthens his character but also reinforces the themes of bravery and self-discovery.