There's no way to be certain without reading the novel. But perhaps there's a protagonist who has just inherited the recipe for the black cake and in the process of making it, discovers a whole new side to their family's history. There could be other characters like siblings or neighbors who play important roles in either helping or hindering the protagonist's exploration of the black cake's significance.
I don't know as I haven't read this novel. But usually, main characters are those who drive the story forward. They could be the ones with the most complex personalities or the ones with the biggest goals in the story.
It's possible that the main characters are people from different backgrounds but are united by their love or hatred for the black cake. There could be a local baker who is known for making the best black cake in town and a customer who has a special connection to the cake. As the story progresses, their lives become intertwined through the black cake and their individual stories unfold.
There could be many possibilities. Maybe it's an old woman who has been making the black cake for decades and she is one of the main characters. Or it could be a young girl who is learning the recipe of the black cake from her grandmother, so both of them would be main characters. Also, if the black cake is part of a community event, the organizer of that event could be a main character in the story related to the black cake.
I'm not sure specifically since I don't know the details of this 'Black Cake A True Story'. But it could be the person who bakes the cake, perhaps an elderly grandmother who has a special recipe.
I'm not sure as I haven't read it, but it could be the baker of the black cake.
I don't know who the author of the 'black cake novel' is. There could be many relatively unknown novels with this name, or it might be a new release that I'm not familiar with.
The main characters are Fionna and Cake, of course. Fionna is a really interesting character with her own personality and goals. Cake also has a distinct role and they are often together in their adventures.
Since I don't know the specific 'christmas cake story', it could be a baker as a main character. The baker who painstakingly creates the perfect Christmas cake.
I don't have the details of this story, so I can't say for sure who the main characters are. It could be a child who is having a birthday and their family members like parents and siblings.
The cake princess is surely one of the main characters. Then perhaps there is a prince from another kingdom who falls in love with her because of her unique relationship with cakes. And there could be a villain, like an evil chef who wants to take over the princess's cake - filled land.