Carnaxus said:
Original characters are not always fan characters; see Mae by Paige for one such example.

The entire point of "original character" is to specify that you have added an original character of yours to an existing franchise, as opposed to a canon character. It's just a more "professional" way to say fan character.

If your character is COMPLETELY original and appearing in a completely original world of yours, then you don't need to make that distinction. It becomes a moot point.