Well, in a typical 'Long Princess Story', aside from the princess, there could be her loyal servants or friends. They might be there to support her through her adventures or challenges. There could also be her family members, like her father the king or her mother the queen, who play important roles in her life, whether it's guiding her, or causing some family - related drama.
Since we don't know the exact 'Long Princess Story', it's difficult to say. But generally, in a princess - centered story, there would likely be the princess herself. There might also be a prince who could be her love interest, or a villain like an evil witch or a power - hungry nobleman who creates obstacles for the princess.