In 'The Sound of Thunder' short story, Eckels is the main character. He is a man full of bravado at the start, excited to go back in time and hunt dinosaurs. The safari guide Travis also plays a crucial role. He is the one who warns Eckels about the potential consequences of their actions in the past. There are other minor characters too, but Eckels and Travis are the ones who drive the story forward with their actions and decisions.