In fanfics, 'ofc' stands for 'of course'. It's a way to express something in a more casual and abbreviated manner. Writers might use it to make the text seem more conversational and relatable.
One great 'Ofc Heartbroken Twilight Fanfiction' story could be about a character who is heartbroken because they lost their chance with a Twilight character. For example, a story where an original female character (Ofc) had deep feelings for Edward but he chose Bella. The heartbreak could be explored through her inner thoughts and how she copes with seeing them together.
In the Levi King story, Levi King might be a very interesting character. He could be a person with a special talent. For instance, he might be an excellent musician who uses his music to bring joy to people or to tell important stories. Or he could be a great athlete, competing in some sort of challenging sport and showing great sportsmanship.