It could be the kittens themselves. Maybe there's a lead kitten that has special abilities or a unique backstory related to the Attack on Titan world. For example, it could be a kitten that was experimented on by the same people who created the titans.
Armin could also be a main character. His intelligence and strategic thinking would play a role if Sakura is involved in the fight. He might be the one to figure out how to best utilize Sakura's unique skills and abilities in the battles against the Titans, and they could form a friendship based on mutual respect for each other's capabilities.
The main characters include Eren Yeager. He is a very important character with his determination to fight the Titans. Mikasa Ackerman is also a main character, known for her great combat skills and her loyalty to Eren. Armin Arlert is another key character, being intelligent and often coming up with strategies against the Titans.
Eren might still be one of the main characters. Since he is such a central figure in the main series, it's likely he plays an important role in the short story as well, perhaps in a different situation or with a new aspect of his character explored.
Mikasa Ackerman is another important character. She is highly skilled in combat and is very protective of Eren. Her loyalty to Eren is a significant part of her character.
The old story can give characters a sense of purpose. For instance, if their ancestors had a role in the old story, they might feel compelled to continue that legacy.
No. Fanfiction is created by fans independently. Characters in the original Attack on Titan have no direct influence on the fan - made stories. However, their actions and personalities in the original work inspire the fanfiction writers.
There's Angel, who is a central character with his own story arc. He has to face many challenges in this pre - main - story world. Then there are his comrades like Kasugabe. They all have different personalities and motives that drive the story forward. For instance, some are more focused on revenge against the Titans, while others are trying to find a more peaceful coexistence.
Eren could definitely be a main character. He could use his Titan -shifting abilities in a unique way during the Halloween - themed events. Maybe he discovers a new power related to the spooky atmosphere. Mikasa would also be a great main character. She could be protecting Eren and the others from any unexpected threats that come with the Halloween setting.
Well, it's likely that Eren would still be one of the main characters. After all, he's a central figure in the original 'Attack on Titan' story. He might be the one most affected by seeing the future and could play a crucial role in trying to change it.