The main characters in 'Shutter Island novel' are Teddy Daniels and Chuck Aule. Teddy Daniels is the central figure, a man haunted by his memories of the war and his own personal tragedies. He's on a mission to uncover the truth on Shutter Island. Chuck Aule is his partner, and while he seems like a typical supporting character at first, as the story unfolds, we learn that he has his own significance in the overall narrative. There are also other characters in the mental institution on the island, such as the doctors and patients, who play important roles in creating the complex and mysterious atmosphere of the story.
In 'Shutter Island novel', the two most important characters are Teddy Daniels and Chuck Aule. Teddy is a complex character with a troubled past. He's a U.S. marshal who is determined to find out what happened to the missing patient. Chuck Aule is his sidekick, more or less. He's there to support Teddy in the investigation, but as the story progresses, we see that their relationship and their individual roles are more nuanced than they first appear.