The main character is Anna, no doubt. Her memory - erased state is what the fanfic is based on. Elsa is very likely to be a main character. In the 'Frozen' world, she has a special connection with Anna. Their relationship would be at the heart of the story, especially with this new complication. Kristoff, as Anna's significant other, would be involved. He might be the one to go on adventures to find a cure for Anna's memory loss. And Olaf, that lovable snowman, would be there to add his unique charm and be a source of comfort and support for Anna throughout the story.
Anna is the central figure here as the whole concept revolves around her memory loss. Elsa is bound to be a main character too. Given their strong bond in the 'Frozen' story, Elsa would play a crucial role in dealing with Anna's situation. Kristoff, being Anna's love interest, would also be a key character. And Olaf, with his innocent and caring nature, would surely be there to try and cheer up Anna and assist in any way he can.
I'm not sure specifically as I haven't read this particular 'Frozen' fanfic. But generally, if Anna has her memories erased, it could be about how she copes without her past knowledge, how her relationships change, and how she might rediscover herself or things from her past in the context of the 'Frozen' world.
Obviously, Anna is one of the main characters. Elsa might also play a significant role, as their relationship is central to the Frozen story. Olaf could be there too, providing some comical relief and friendship to Anna during her adventures.
A new villain, a dark ice - wizard from a far - off land, could be the kidnapper. He might have heard about Anna's connection to Elsa and her powers and wants to use Anna to control Elsa. He kidnaps Anna and takes her to his frozen lair.
Well, of course, anna nishikinomiya herself is a main character. She is often the center of the story, driving the plot forward with her actions and decisions.
Well, Luffy would obviously be one of the main characters. Since it's about his memories, he's at the center of it all.
Obviously, Anna herself is a very important character as she is the one who is pregnant. Kristoff would also be important as he is Anna's husband and would be there to support her through the pregnancy. Elsa could also play a crucial role, perhaps using her powers to protect Anna and the unborn child.
The main character is the boy who goes through the conversion therapy. His father also plays a significant role as he is part of the reason the boy is sent to the therapy.
Satoru Fujinuma is one of the main characters. He has the time - travel ability.
The main character is the boy who goes through the conversion therapy. But there are also likely other characters such as his parents and the people running the therapy program.
Since it's a Naruto fanfic, it's possible that Naruto Uzumaki is one of the main characters. He might be the one who first discovers the frozen flame or is drawn into the mystery surrounding it. Other likely candidates could be Kakashi, who could be guiding the younger characters in understanding this new and dangerous element. And perhaps there are some original characters created specifically for this fanfic that also play major roles.