One of the characters

The other main character is Peeta.
He is in the same age as Kattnis.
He is the one Kattnis won The Hunger Games with.
He lives in district twelve there Kattnis also lives.
He lives with his parents and they are all running a bakery.
Peeta is having a crush on Kattnis since the begining of the trilogy, and this is one of the reasons to why they both won in the first book "The Hunger Games"