Katarina is from Pescatore Island in the South Blue, it's really small and far from any other islands. It is full of fishermen because that's the only steady food supply. Merchant ships from Baterilla often stop there before heading to their actual destination.
@Shimakage Thunder Sorry for the hiatus, I hoped Emmii would get on. I'm going to make another character so that there is another male in the story and I am not going to use Lucy until we have more people, if we ever have more people. Now we'll post more regularly.