I'm not sure of a specific fanfiction with this exact premise, but you could start by looking on popular fanfiction websites like Archive of Our Own or FanFiction.net. Try searching for 'Fem Naruto Champion Cynthia' in the search bars there. There might be some hidden gems waiting to be discovered.
One common theme is adventure. Since they are both champions in the Pokémon world, they often go on epic journeys together in these fanfics. Another theme is friendship. Their bond as fellow champions is explored, showing how they support and learn from each other.
A possible plot could be that Fem Naruto is a reincarnation of someone important in the Pokemon world related to Cynthia. She has memories of her past life in Naruto's world but is now on a quest in the Pokemon world. She is drawn to Cynthia because of some unknown connection. As she gets closer to Cynthia, she uncovers secrets about her past and the two of them end up on a journey together to protect the Pokemon world from an ancient threat.
One popular 'Ash Champion with Cynthia fanfic' might be 'Journey to the Summit'. It's a great read that showcases their adventures together in a fictional Pokémon world. In it, Ash and Cynthia team up to face powerful foes and discover new Pokémon regions.
A really interesting plot could be that there's a strange phenomenon causing Pokemon to lose their powers randomly. Ash and Cynthia have to figure out the cause together. Along the way, they discover some long - forgotten secrets about the origin of Pokemon powers. Their journey involves visiting ancient ruins, talking to wise old Pokemon trainers, and facing off against some bad guys who are trying to take advantage of the situation.
Cynthia's Pokemon are generally very strong and well - trained. When combined with Ash's Pokemon, who have a lot of heart and determination, there could be some amazing interactions. Ash's Snorlax, for instance, could befriend Cynthia's Milotic. They might not seem like an obvious pair, but their laid - back personalities could make for a fun dynamic. Meanwhile, Ash's Infernape could look up to Cynthia's Lucario as a role model for power and control, leading to some intense training sessions between the two Fire and Fighting - type Pokemon.
Without having read 'Kalli the Champion Novel', we can only speculate. But it might revolve around the theme of heroism. Kalli is named as a champion, which could imply that she is some sort of hero in the story. The novel might explore what it means to be a hero, the responsibilities that come with it, and how Kalli rises to the challenges presented to her in order to fulfill that heroic role.
The main theme could be about perseverance. In many novels with such a title, the characters often face numerous challenges and they have to keep going, showing that they have the heart of a champion, which is the will to succeed no matter what.
Cynthia is likely a person who has a very challenging life due to her weight. She might be someone who has been through a lot of emotional and physical hardships because of being overweight. In the context of 'my 600 lb life', she is probably a participant in the program trying to lose weight and regain her health. She could have different personal stories, like her relationship with food, family support or lack of it, and her own motivation to start this difficult journey.