How are cray and Darius different from one another

Darius is a friendly Peacekeeper who is replaced after Thread takes over. He is enslaved by the Capitol and turned into an Avox, a mute servant, and forced to serve the District 12 team at the Training Center. Darius is sensitive to the people of the district. Katniss feels responsible for his punishment. Cray is not a nice person. He is a predator, infamous for paying young women to sleep with him. He cares nothing for people in the district.