In 'The Gruffalo', the main characters are the mouse and the Gruffalo. The mouse is a clever little creature who outsmarts the Gruffalo. The Gruffalo is a big, scary - looking beast.
There are a variety of main characters in Julia Donaldson short stories. In 'Zog', Zog the dragon is a main character. He is eager to learn and improve himself at dragon school. Then there are the princess and the knight who also play important roles in the story. They are not the typical 'damsel in distress' or 'fierce knight' but have more complex personalities.