An idealistic former District 2 resident turned rich Capitol mentor and Academy student, Sejanus’s unbending moral fiber and bullheaded determination to do good are a bright counterpoint to the ambitious and calculating Coriolanus. Sejanus has an unwavering commitment to what he believes is right, even amidst the brutality of the Hunger Games.  

Unlike Coriolanus, Sejanus comes from a family enriched by war. He grows up with a great deal of affluence, but because he comes from District 2, many people in the Capitol’s “old money” circles feel as if he is not good enough to associate with them or their children. When he arrived at the age of 8, he was viciously bullied by the other children in his class. Children in the Capitol are raised to believe that anyone from the Districts is a lesser form of life, and reinforcing this prejudice is part of how the Capitol retains its enormous sway over both its citizens and the Districts themselves. Because Coriolanus ignored him rather than bullying him, by the time they reached the age when they could act as tribute mentors, they developed an uneasy friendship of necessity. Although Coriolanus is never as committed to the relationship, Sejanus begins to think of him as a brother, treating him as a confidante and relying on him for advice and support. 

Sejanus feels no pride in the Plinth fortune. Rather, he’s constantly reminded of the violence of his family’s legacy. This disgust manifests in his fierce empathy for the tributes, particularly his former classmate from District Two, Marcus. He refuses to play by the Capitol's cruel rules, even when he suffers socially because he calls out the hypocrisy of his classmates trying to kill other children just like them. However, while Sejanus' intentions are pure, his methods are often impulsive and naive. After seeing Marcus tortured, he makes an ill-fated attempt to martyr himself on live TV as a protest for the Games. It’s only one of many badly planned attempts Sejanus makes to try to fix things. Unlike Coriolanus, the harder Sejanus tries to solve problems, the worse things tend to go. This begins as childlike missteps during the Games which his family can hush up, but quickly becomes a life-threatening liability.