Maybe some survivors from areas that were previously unmentioned. They could bring new skills and perspectives to the story.
There could be new military leaders or strategists. As the story progresses, new people with different ways of fighting Titans will likely appear. They might have unique weapons or combat styles that we haven't seen before. Also, there could be civilians who end up playing important roles, like those who discover something crucial about the Titans or the world they live in.
In the new Attack on Titan story, we might see new characters from other regions outside the main areas we've known so far. These could be exiles or refugees who have their own stories and motives. They could be connected to the Titans in some way, perhaps having knowledge of a different type of Titan or a way to control them. There may also be new characters within the existing military or political structures who rise to prominence due to the changing situation. For example, a young recruit who shows extraordinary potential in dealing with the new threats posed by the Titans.
It's hard to say exactly. But maybe there will be some foreign soldiers from lands outside the walls that we haven't seen before. They could bring new fighting styles and different perspectives on the Titan problem.
Competing authors or those in the publishing industry who see the new novel as a threat to their own works or market share. If a new novel is getting a lot of hype, they might try to find ways to downplay it through negative comments or reviews.
Lovi (Lovino Vargas from Hetalia) and Levi (from Attack on Titan) could be a likely pair. They both have that tough - exterior and are often seen as no - nonsense characters. Their interactions could be full of bickering and grudging respect. Another possible pair could be America (Alfred F. Jones from Hetalia) and Eren (from Attack on Titan). They are both quite headstrong and have a strong sense of justice, so they might team up to fight the Titans and try to bring about change in the world.
Obviously, Eren as a baby is the central character. But we can also expect to see his family members like his father, Grisha. His mother, Carla, would also be an important presence as she plays a significant role in Eren's early life.
The Colossal Titan is one of the scariest. It's so huge and can cause massive destruction just by its appearance. It can break through walls with ease, leaving the humans defenseless.
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 Yeager is extremely important. He is the main protagonist and his transformation into a Titan is a key part of the story. Mikasa Ackerman is also crucial. She is a very strong fighter and has a deep bond with Eren. Levi Ackerman is important too. He is known as humanity's strongest soldier and plays a vital role in battles 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.
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.
The new Attack on Titan story could bring a lot of surprises. We may witness the expansion of the world beyond what we've seen so far. New cultures and groups of people might be introduced. Regarding the plot, it might focus on the consequences of the previous events. The remaining characters will have to deal with the aftermath of Eren's actions. There could be a search for a new way to coexist with the Titans or to completely eradicate them once and for all. And with new Titans emerging, the power dynamics will surely change, leading to more complex and exciting storylines.