Beatrice Prior (Shailene Woodley) was born into an Abnegation (the group that values selflessness) family, but she chooses to join the Dauntless faction (the group that values bravery). She learns that she's Divergent (meaning she doesn't fit into just one faction) and must keep this information secret, as the leaders of the futuristic society view it as a threat.
Tobias "Four" Eaton (Theo James) is one of the instructors in the Dauntless faction. He leads the new members through initiation. After Beatrice meets him, she becomes interested in him as much more than a teacher.
Christina (Zoe Kravitz) is a fellow transfer to Dauntless. She comes from Candor (the group that values honesty) and becomes a close friend of Beatrice's.
Eric (Jai Courtney) is the leader of the Dauntless faction. He's been competitive with Four since their own initiation.
Max (Mekhi Phifer) is one of the Dauntless leaders. He meets new initiates and tells them to jump from the rooftop to get to the entrance of the Dauntless compound below. He oversees their training.
Peter (Miles Teller) is another Dauntless initiate. He comes from the Candor faction, and is extremely competitive with Beatrice.
Tori (Maggie Q) is a member of Dauntless. She administered Beatrice's aptitude test, discovering and telling her that she was a Divergent.