A young adventurer could be a great main character. They are always exploring new places, so it's likely they could end up in the wrong place at the wrong time and get kidnapped by witches.
A regular person with a strong will could be the main character. They don't have any special powers, but their determination and cleverness help them survive and eventually escape from the witches. They might use their knowledge of the normal world to find weaknesses in the witches' lair or routines, like using simple household items as makeshift weapons or tools for escape.
Perhaps a magic - user who has a different kind of magic from the witches. The witches might be interested in this unique magic and kidnap the character to study it or steal it. This would create a lot of conflict as the character would fight to keep their magic and escape the witches' clutches. They could also use their magic in unexpected ways to outwit the witches during their captivity.
It could be a young adventurer. This type of character would be full of curiosity and a sense of exploration. Their kidnapping by pirates would be a major setback to their adventure plans, but they would also be quick to look for ways to turn the situation around.
It could be a young woman who is a stowaway on a ship and gets discovered and kidnapped by pirates.
It could be a young child who strays too close to the sewers where Pennywise lurks.
It could be a new character created specifically for the fanfiction. Maybe a young scientist who is working on a project related to the super - soldier serum. Since Bucky has a history with the serum, this would create an interesting dynamic.
Perhaps it could be a minor character from Twilight who somehow ends up in a situation where they are kidnapped by a creeper. This would give the writer a chance to explore that character more deeply and in a completely different context. For example, a character like Jessica from Twilight could be the main character. She's not a central figure in the original story, but in this fanfiction, she could have a whole new adventure.
It could be Robin, the Boy Wonder. If Catwoman kidnapped Robin, Batman would surely be on a mission to rescue him. Robin is young and inexperienced compared to Batman, so he could be an easy target for Catwoman, and his rescue would make for an exciting story.
It could be an over - enthusiastic fan who has always wanted to meet the Jokers. They get kidnapped by accident during one of the Jokers' wild stunts, and then they have to deal with the crazy situation.
The boy could be named Tom, a curious and adventurous 15 - year - old. He's not afraid to explore new things, which is how he ends up meeting the witches. The witches could include a young and kind - hearted witch named Lily, who is still learning about her powers. And an older, more experienced witch named Agatha, who is initially skeptical of the boy but later warms up to him.
Hermione Granger could be one of the main witches. She's extremely intelligent and powerful, and in the fanfiction, she might be involved in some secret magical research or adventures.
A detective - style character could be the main character. This could be a human or an animal detective who is hired to find the kidnapped lemon. They might have a special connection to fruits, like they grew up on an orchard, and they feel a sense of duty to rescue the lemon. They would then go on a journey, following clues and interrogating suspects.