Obviously, Shoko is a main character. She is often depicted as a tough and resourceful girl with her own set of skills. Another important character could be Finn. Finn might cross paths with Shoko and they could either become friends or rivals depending on the plot. Jake, Finn's loyal dog, could also play a role, perhaps helping or hindering Shoko's plans.
Lady Rainicorn could also be an interesting character to pair with Shoko. Since Lady Rainicorn can't speak English (in the normal sense), there could be some really fun and comical interactions as Shoko tries to communicate with her. And they could also get into some interesting situations together, like flying around on Lady Rainicorn's back to reach some far - off place.
One great 'Adventure Time Shoko' fanfiction could be about Shoko's adventures in the Land of Ooo before Finn and Jake. It might explore her unique magic and how she interacted with the early inhabitants. Maybe she had a run - in with the Ice King when he was still a bit more menacing and she had to use her wits to escape.
The comic has a unique story and interesting characters that draw readers in.
One idea could be Shoko discovers a new, hidden realm in the Land of Ooo. She teams up with Finn and Jake to explore it and uncovers ancient secrets that could change the whole world of Adventure Time.
One great 'Adventure Time Shoko' fanfic is 'Shoko's Adventure' which follows Shoko on a journey through the Land of Ooo. It has interesting character interactions and a unique plot.
First, study the existing Adventure Time lore, especially about Shoko. Know her character traits, her relationships in the show. Then, come up with a unique idea. It could be a new adventure she goes on, or a different way her relationships develop.
The Ice King can be a key character too. Maybe he tries to kidnap Minerva for his own strange reasons, thinking she can be his new princess. Marceline the Vampire Queen could also be involved. She might be Minerva's ally or foe depending on the plot of the fanfiction. There are also other minor characters from the Adventure Time series that can play important roles in Minerva - related fanfictions.
Princess Bubblegum's future self could be a main character. She might be leading a resistance against a new tyranny in Ooo. Also, the Candy Kingdom could have new heroes from within its walls, like a young gumdrop who discovers a hidden power within herself and becomes a key figure in the future battles. Additionally, a future version of Marceline could be involved, perhaps she has become a mentor to the new generation of adventurers.
The main characters are Leo and Blake, of course. They are likely to be the ones driving the story forward, getting into all sorts of adventures in the Adventure Time universe.
Well, the si gamer is obviously one of the main characters. Then there could be Finn and Jake who might interact with the si gamer. Finn with his adventurous spirit and Jake with his shape - shifting abilities would make for interesting interactions with the si gamer.