Flavius is one of Katniss's prep team members that do their best to make her look good enough to get sponsors during the chariot ride and interviews.
During this time, his appearence disgusted Katniss when she first saw him. Flavius appreciated Katniss for not whining when they were dressing her, waxing her hair, etc. When they were done with her, Flavius said Katniss looked good. Before the interviews, he and the rest of the prep team went to the Training Center to prepare Katniss again so Cinna could begin designing her dress for the interviews. When Katniss came back alive from the Games, he and the other prep team members were ecstatic.
Flavius was excited for Katniss since Katniss was going to be lucky enough to mentor the tributes for the third Quarter Quell in her first year of being a mentor. Flavius went along with the others on the Victory Tour to help Cinna in dressing Katniss. Flavius, along with his comrades, arrived early to Katniss' new home in the Victors' Village to get her ready for her wedding dress shoot. Flavius and the other members were conversing about not having seafood for weeks, electronic gadgets or fabric they needed and Katniss was able to figure out it was due to rebellion in District 3, 4 and 8. Flavius cried when President Snow announced that the third Quarter Quell would reap past victors. After telling Octavia to leave since she couldn't contain herself, he shortly left after since he couldn't either. Flavius said his final goodbyes, on behalf on the whole prep team, to Katniss before she entered the arena.
Flavius, along with the other members of the prep team, were taken ho
stage by District 13. President Coin thought she would be doing Katniss a a favor if she captured and tortured them for her. Since Flavius and the others were not fed enough, Octavia stole some bread but was caught. The prep team was thus taken into a room and beaten until Gale distracted the guard and Katniss entered the room to discover her beaten up prep team. Katniss demanded that they would be taken to her mother for treatment from their wounds. Flavius recovered, thanks to Mrs. Everdeen, but was still terribly fearful. Flavius and the others prepared and dressed Katniss for the role of the mockingjay. He trembled constantly, still scared of what had happened to them, but trusted Katniss. Katniss took them to eat and he would later often eat with them. The prep team assembled again after President Snow was tried, found guilty and sentenced to be executed. They dressed Katniss up in her mockingjay uniform and watched her during the trial. After Presidents Coin and Snow died, Flavius, Venia, and Octavia most likely went back to the Capitol or resided in one of the districts.