Not having read the novel, I can only speculate. The main characters in 'chosen ones a novel' could be individuals with distinct personalities. Maybe there's a strong - willed leader type who is among the chosen ones and has to rally the others. There could also be a character who is initially reluctant to be part of this 'chosen' group but eventually comes around. And perhaps there's a character who has some sort of hidden power or knowledge that is crucial to the whole 'chosen ones' concept in the novel.
Since I haven't read 'chosen ones a novel', it's hard to say exactly. However, the main characters are likely to be those who are singled out as the chosen ones. They might be from different backgrounds, like a young orphan, a grizzled old warrior, and a brilliant but shy scholar. These diverse characters could bring different skills and perspectives to whatever task or journey they are chosen for.
I don't know who the main characters are as I haven't read the novel. But they could be ordinary people who are suddenly thrust into extraordinary circumstances because they are the chosen ones.