The main character is surely the mouse. It is the center of the action, always on the move, being chased. The other character would be the 'chaser'. In a traditional setting, this would be a cat. The cat represents the threat to the mouse. Their relationship of chase and escape forms the core of the story. Without the cat, the mouse's clever escapes wouldn't be as exciting, and without the mouse, the cat would have no target to pursue.
The main characters are the country mouse and the city mouse.
The town mouse and the city mouse are the main characters. The town mouse represents a more simple and peaceful lifestyle. It's used to the quieter, less hectic environment of the town. The city mouse, on the other hand, represents a more fast - paced and luxurious (but also more dangerous) lifestyle of the city. Their different personalities and ways of life are what drive the story forward.
Since we don't have the full story, it could be a young adventurer as the main character. Someone full of curiosity and courage, eager to reach for the stars.
I'm not sure as the details of 'the big catch story' are not given. But it could be a fisherman as the main character if it's a fishing - related story.
Since I don't know the exact 'game of catch story', it could be a group of children. Kids often play catch, so they might be the main characters.
The main characters are the city mouse and the country mouse, of course. They are the ones whose different lifestyles and experiences are contrasted throughout the story.
There are two main characters. The country mouse is simple - minded and used to a quiet, rural life. He is content with his simple food like grains. The city mouse is more sophisticated and used to a life of luxury in the city. He has access to fancier food but also faces more danger, like from the cat in the house.
The main characters are, as the title suggests, a man and a mouse.
In a 'big mouse story' that focuses on the big mouse's family, the main characters would be the big mouse, its parents, and its siblings. They could be living in a nest together, and the story could be about how they support each other. For instance, the big mouse might be the strongest one in the family and it has to protect its smaller siblings from danger.
Since I don't know the exact story, I assume the main character is the Christmas mouse. There might also be other characters like the people in the house where the mouse lives, or maybe some pets in the house.