Goku's power grows immensely, yet his core personality remains simple and focused on fighting. He prioritizes strength and sparring over personal relationships, a consistent trait throughout his journey.
Naruto transforms from a rejected outcast into a trusted leader, driven by a desire to protect the very village that once shunned him. His bonds with friends heal his loneliness and define his growth.
Luffy's core desires for adventure and nakama remain, but his journey forces him to mature through loss and intense training. He evolves from a simple pirate into a feared, yet still goofy, emperor.
Ichigo evolves from a rage-filled teen burdened by grief to finding inner peace. Losing and regaining his powers, plus discovering his father's secrets, reshapes his understanding of strength.