I'm not sure specifically as I don't know the exact 'the changeling science fiction' work. But generally in such stories, there could be the changeling itself as a main character. There might also be a scientist or an investigator trying to figure out what the changeling is all about.
In 'the changeling science fiction', it's hard to say for sure without more details. However, it's common to have a protagonist who is somehow connected to the changeling. Maybe it's a person who discovers the changeling and has to deal with the consequences. There could also be an antagonist who wants to use the changeling for their own evil purposes, like a power - hungry villain.
Since we don't have the full story of 'the changeling science fiction', we can only speculate. There could be a young, curious character who stumbles upon the changeling and becomes involved in the mystery. There might also be an older, wiser figure, perhaps a mentor - like character, who helps the main character understand the nature of the changeling and the science - fictional world it inhabits.
Well, in 'the changeling science fiction', a possible theme is adaptation. Just like in a lot of sci - fi, the characters have to adapt to new and strange situations. If there are changelings in the story, they might be adapting to a new form or a new environment. Also, the theme of mystery is likely. The concept of a changeling is often mysterious, and in a science - fiction setting, it can add to the overall enigma of the plot.
In many 'the changeling fanfic' stories, the main characters are likely to be changelings. They might be portrayed in different ways, like a young and naive changeling trying to find its place in the world, or an older, more experienced changeling who is trying to change the ways of their kind. Other possible main characters could be those who are affected by the changelings' actions, like a human village leader who has to deal with the presence of changelings near their village.
I'm not entirely sure as I haven't read the specific 'The Changeling Novel'. But usually in such a novel, there would be the changeling character itself, perhaps a human who has been transformed. There might also be a mentor - like figure who helps the changeling understand their new state.
Some main characters in science fiction are often extraordinary individuals. For example, in 'Star Wars', Luke Skywalker is a central figure. He starts as a farm boy on a remote planet and is drawn into a grand galactic struggle. His journey of self - discovery and his development of Jedi powers make him a very engaging main character. Another is Ripley from the 'Alien' series. She is a strong and resourceful woman who has to fight against terrifying alien creatures in the vastness of space, representing human resilience in the face of the unknown.
In 'the changeling old story', the key characters are the changeling, which is often a mysterious and magical entity. Then there are the human parents or caretakers of the child. They are the ones who notice the strange behavior of the supposed changeling and try to deal with the situation. There might also be some wise old women or men in the story, who are considered to have knowledge about how to deal with changelings, like knowing certain spells or rituals to get the real child back.
Without more information about this 'the changeling a true story', it's difficult to determine the main characters. However, in a typical changeling story, there would likely be the parents or guardians who first notice something strange about the child. There might also be some sort of authority figure or expert who gets involved in trying to figure out what's going on, whether it's a doctor, a psychologist, or a local wise person.
The most important character is Christine Collins. She is at the center of this true story. There are also the police officers who play a negative role as they try to deceive her and cover up their actions. And of course, there is the mystery surrounding her missing son.
I'm not sure exactly as I haven't delved into it deeply, but it's likely to have a central character who is at the heart of the 'changeling' situation, perhaps a victim of some sort of misrepresentation.
The main characters often include the changeling itself. It's this mysterious being that takes on the form of the person it replaces. The family that the changeling infiltrates is also very important. The parents will be the ones to first suspect that something is wrong. There could also be a local expert, like a priest or a shaman in some versions, who tries to deal with the situation of the changeling in the family.
It's hard to say without more information about the specific 'the changeling fantasy novel'. But typically, there would be the changeling character itself. There might also be the person or family that the changeling is replacing or interacting with. And often, there are other magical beings or characters who are aware of the changeling's true nature and play a role in the story.