I'm not sure as I haven't read this novel. So I can't tell you who the main characters are.
In the 'Shark in the Dark Story', the most obvious main character would be the shark. But depending on the nature of the story, there could be other important characters too. If it's a story about the shark's journey, perhaps there could be a seagull that the shark sees flying above the water's surface during the day before it goes into the dark depths at night. Or there could be an old, wise octopus that the shark encounters in a dark cave, and they have some sort of interaction. Maybe there are also other sharks that the main shark has a relationship with, like a rival or a mate.
Since we don't know the exact story, it could be the friendly shark itself as the main character. There might also be other sea animals like fish, dolphins, or turtles that interact with the shark and are important characters in the story.
Since I don't know the story well, I can't say for sure. But the shark must be one of the main characters.
It's hard to say for sure, but perhaps the main characters are a couple of siblings. The older sibling might be protective of the younger one when it comes to the idea of sharks. And there could be a new kid in town who joins them in their exploration of the shark world. They all together form the main characters who drive the plot of the 'Shark Kids Story'.
Since I don't have access to the story, the main characters could be a fisherman who gets into trouble and becomes shark bait. Or it could be a group of surfers where one of them is in a situation that makes them seem like shark bait. There could also be a marine biologist in the story who is studying sharks and somehow gets too close to the sharks and becomes the so - called 'shark bait'.
Given the title 'shark girl tf story', the obvious main character is the shark girl. But there could be other supporting characters. For example, if the story is set in a coastal town, there might be fishermen who have seen strange things related to the girl. Or if it's a story about her fitting into a new world, there could be other 'creatures' or people in that world who interact with her. There could also be a mentor - like figure who helps her understand and control her new form or abilities if it involves a transformation.
Since I haven't read the 'Shark King Graphic Novel', I can only guess. Obviously, the Shark King would be one of the main characters. There might also be his loyal followers, like other sharks who help him in his rule or adventures.
Since I haven't experienced 'Shark Bait Visual Novel', I can't say for sure who the main characters are. But typically in a visual novel, there could be a brave protagonist who is at the center of the action. Maybe there's a marine biologist character who has a passion for understanding sharks and gets caught up in an unexpected situation. There might also be a sidekick or a mentor - like figure to help the main character along the way.
I think the shark must be a main character. And perhaps there could be some people in the park as well. They would be important as they might be the ones who interact with the shark, either by trying to avoid it or being curious about it.
I'm sorry, I haven't actually read this particular Chinese novel about the shark. So I can't really tell you the main plot.