Maybe there are some antagonist characters as well. They could be the ones creating or contributing to the 'darkness' in the story. For example, they might be bullies if the 'darkness' is related to a difficult social situation, or they could be inner demons if the struggle is more internal.
I'm not sure specifically as I haven't read the 'out of darkness novel' in detail. But usually, in a novel with such a title, there could be a protagonist who is the one trying to get 'out of darkness'. This character might be a young person facing some sort of internal or external struggles.
There could be a mentor - like figure. In many stories, when the main character is in a difficult situation, there is someone who guides them, helps them to see the light and get out of the dark times. This character could be an older person with more life experience in the 'out of darkness novel'.
Often, there will be some sort of antagonist or opposing force. It could be an internal force within the main character, like their own negative thoughts or habits. Or it could be an external factor, such as a difficult person in their life, a harsh social environment, or a challenging situation that they need to overcome in order to get 'out of the darkness'.
I'm not entirely sure as I haven't read the specific novel. But in Turtledove's works, he often has a diverse set of characters. There might be a protagonist who is leading the journey out of the darkness. It could be a regular person who finds themselves in extraordinary circumstances.
It's hard to say exactly without reading it, but often in such fanfictions, there are characters that are either from the original source material it's based on or new characters created specifically for the fanfiction. They could be heroes with special abilities trying to fight against an evil force.
Since I don't know the details of this story, I can't say for sure who the main characters are. They could be ordinary people who found themselves in extraordinary circumstances and had to fight their way out of a difficult situation.
The main characters in 'The Darkness Out There' full story might be a young person full of naivete and a sense of adventure. They might be accompanied by a more cynical friend who doesn't believe there is anything good in the 'darkness'. Additionally, there could be an authority figure, like a parent or a village elder, who tries to keep the young ones away from the 'darkness' out of a sense of protection. Their interactions and how they view the 'darkness' would be central to the story.
It's possible that the main character is not even human. Maybe it's a spirit associated with the sakura tree itself. And then there could be other characters like a villain who tries to keep the world in darkness and those who oppose the villain, all intertwined in the story of 'sakura out of the darkness fanfiction'.
I'm not sure specifically as the story isn't widely known to me. But usually in such a story, there could be a brave protagonist who takes the lead in facing the challenges of the 'burning darkness'.
There's not enough information to determine the main characters precisely. However, it could be a side character from the original source material that the author of the fanfiction decides to focus on. This character might have been overlooked in the original but now has their own story of emerging from the darkness, perhaps a character who was bullied in a school - based story.
I'm not entirely sure as it depends on the specific fanfiction. It could be a character who has been through a lot, like a war veteran who has finally come out of the mental and emotional darkness of war. Maybe it's a young person who has overcome an abusive situation at home.
Since it's a novel about 'darkness', there could be a character who is initially innocent but gets drawn into the dark world. There may be a mentor - like figure who tries to guide this character out of the darkness. Or perhaps a group of characters with different motives, some good and some bad, all interacting in the setting of this 'darkness' that the novel portrays.