Gaius Breen was a male resident of the Capitol and a student of the Academy. He was one of 24 top-performing seniors at the Academy selected to be a mentor for the 10th Hunger Games. He was assigned the male tribute from District 9, Panlo.
He was considered a "Citadel brat" and was known for having an endless supply of jokes. He once told Coriolanus Snow a joke about how many rebels it took to tie a shoe. He accompanied his tribute, Panlo, on a tour of the Capitol Arena when the arena was rocked by bombs which been planted by rebels. He was hospitalized for critical injuries, having lost both of his legs. He passed away not long afterwards, during the Hunger Games. His death was announced by Dr. Volumnia Gaul, Head Gamemaker of the 10th Hunger Games. As a special punishment, she sent a drone into the Capitol Arena with snake muttations that she had created.
- The Ballad of Songbirds and Snakes, Chapter 19