Fulvia

Fulvia, introduced in Mockingjay is Plutarch Heavensbee's assistant. She played a big role in planning an escape of the tributes from the Clock Arena and has been a part of the rebels for a long time.

She also is originally in charge of the propos portraying Katniss Everdeen as the Mockingjay. As such, Fulvia takes it quite personally when Katniss doesn't do well with the lines she is given to read. Katniss is very bad at the first few propos, and it isn't until she starts actually going to places where the rebels are fighting that the propos are decent enough to use. Fulvia wasn't in charge of these propos, however.