I don't have enough details to know the main characters. But they could be survivors if the story is about a disaster - like a brave sailor, a resourceful young person, or an experienced adventurer.
There's no way to be certain about the main characters without reading the graphic novel. But some possible characters could be a group of pirates who use the 'bad island' as their base. They might be led by a ruthless captain. Another could be a young orphan who discovers a hidden power on the island and has to face the challenges that come with it, while also dealing with the other 'bad' elements of the island.
I'm not sure exactly who the main characters are without reading it, but usually in a story like this, there would be a strong leader type. Maybe someone with survival skills or knowledge.
Maybe there are some fearless explorers as main characters. They might be on a quest for knowledge or treasure on Skull Island. There could also be a character who has a special connection to the island, like a descendant of an ancient tribe that once lived there.
I'm not entirely sure as it can vary depending on the specific adaptation of the story in the graphic novel, but often there is a protagonist who is investigating something strange on the island.
There could be a lead 'bad girl' who is the most rebellious and fearless. She might be joined by her friends or other girls who she meets on the island. Their personalities could range from sassy and outspoken to cunning and resourceful, and together they form the main characters in this 'bad girl island story'.
I'm not sure exactly, but probably some characters who are initially seen as villains.
The main characters in 'bad friends graphic novel' could be diverse. There may be a character who is a bit of an outcast, someone who has a troubled past. And there could be others who are drawn to this character for various reasons. They form this group of 'bad friends' and through their interactions, the story unfolds. Maybe there's a leader - type character who is constantly getting them into trouble and a more timid character who is always on the verge of leaving the group but never quite does.
Without more information, it's impossible to say who the main characters are.
I don't have enough information to say who the main characters are. It could be anyone from a troubled anti - hero to an ordinary person who has made some bad choices and now has to face the consequences.
Since I haven't read it, I can't say for sure. But it's likely that the bad sister herself is a main character. There might also be other family members like her parents, siblings (if she has more than one), or maybe a best friend who is either influenced by her or trying to change her.
I don't have enough information to say for sure. But surely there would be the 'bad doctor' as a main character. There might also be patients who are affected by the doctor's actions, or other medical staff who either oppose or are complicit in the doctor's bad behavior.