What character has the biggest change from the begining of th book till the end and what was the change?

I would say that would be the protagonist Thomas. He arrives in the Glade with no knowledge of who he is or was. He only remembers his name and nothing else about his life. He is scared and confused. Thomas proves to be brave, loyal, and clever, with isolated telepathic powers and a very limited memory of previous knowledge of the Maze. Soon after arriving in the Glade, Thomas makes both friends and enemies and proves a leader among the boys.