I don't know exactly, but they might be a diverse group. There could be a young and adventurous protagonist who initiates the journey of leaving the world behind. There may also be an older, wiser character who serves as a guide or mentor. And perhaps there are some supporting characters with their own backstories and motives for joining this departure from the known world. They all come together to form an interesting cast that drives the story forward.
Since I haven't read the book, I'm not sure who the main characters are. But they could be ordinary people who are looking for a change in their lives.
Without having read the book, it's hard to say for certain. However, it's common for such stories to have a central character who is disillusioned with their current life. This character could be someone who feels trapped in a job, a relationship, or a particular social environment. Then there might be other characters around this central figure. Some could be friends or family members who are either dragged along on this journey or are there to try and stop the main character from leaving. And there could also be characters they meet along the way, in the new world they enter, who add more depth and complexity to the story.