How has Paul D's narrative changed from earlier chapters? (prt3: chp2-3)

Paul D is a dynamic character. In his earlier days, Paul D is described as quiet and strong with a ,"tobacco tin" rusted shut as a heart. Paul D changes into a vulnerable man. He drinks and is haunted by his days as a slave. Instead of withstanding the blows and buffets of his world, he laments his life both past and present.