Obviously, the main characters are Black Jack and Bolton.
I'm not sure specifically as there could be many stories named like that. It might be about two characters named Black Jack and Bolton. Maybe it's an adventure they had together, or a relationship between them.
Since it's a Jack Ryan story, Jack Ryan is likely to be one of the main characters. But without more information, it's hard to say who else might be involved. There could be some new characters created specifically for this 'Black Jack' story, or it could also feature some recurring characters from the Jack Ryan series.
If the 'jack black cave story' is based on a well - known story, and if Jack Black is a real person's name being used for a character, then Jack Black would be one of the main characters. But without more information, it's difficult to determine if there are other main characters. Maybe there could be a sidekick or an antagonist like a cave - dwelling monster.
Since I don't know the exact 'black jack novel', it's hard to say. But it could have a character named Black Jack as the main character. There might also be a love interest, like a female character who plays an important role in his life. And perhaps an antagonist, someone who is constantly opposing Black Jack in his pursuits.
Perhaps in a 'black jack story' set in a fictional world, the main characters could be Blackjack masters who travel around competing in high - stakes Blackjack tournaments. They might have unique abilities or strategies related to the game. There could also be antagonists, like cheaters or those who try to disrupt the fair play of the tournaments.
The main character is of course Dr Black Jack himself. He is a brilliant and mysterious doctor.
In the 'jack and jill the story', the main characters are, of course, Jack and Jill. These two characters are what the story is all about. They are the ones who experience the adventure of climbing the hill and facing the consequences when things go wrong on their water - fetching mission.
Obviously, the main characters in the 'jack and tim story' are Jack and Tim. But we don't know what roles they play yet, whether they are friends, enemies, or something else.
The main characters are Jack and the giant. Jack is a young boy who climbs the beanstalk. The giant is a large and fearsome character who lives at the top of the beanstalk in a castle in the sky.
The main characters are Jack, Jack's mother, and the giant. Jack is the protagonist who climbs the beanstalk. His mother is a part of the story as she is initially angry about Jack trading the cow for beans. And the giant is the antagonist who owns the treasures that Jack steals.