The original story of Princess Ariel is from 'The Little Mermaid' by Hans Christian Andersen. In the original, Ariel gives up her voice to the sea witch in exchange for legs to be with the prince she loves on land. However, the prince marries another, and Ariel is in great pain. In the end, she is given a chance to earn a soul by doing good deeds instead of a happily - ever - after marriage as in the Disney version.
The main characters in the original story of Princess Ariel include Ariel, a young and curious mermaid. The sea witch, who is a rather menacing figure, as she tricks Ariel into a difficult bargain. Then there's the human prince. His presence and Ariel's infatuation with him are central to the plot. Additionally, Ariel's sisters also have a role to play as they are part of her mermaid world and are affected by her decisions.
In the original story, Ariel was indeed white. This was the traditional portrayal in the classic version of the story. It was part of the overall aesthetic and cultural context of that time. However, as times have changed, there have been different interpretations and adaptations that may vary this aspect, but in the very first incarnation, she was white.