In a novel, the male lead is kidnapped at the beginning, and the kidnappers ask him to steal a necklace from his family or something. They know magic and are hunted down.

There could also be a group of villains working together to kidnap Sonic. For instance, a combination of Eggman and some of his more powerful robot creations along with a couple of other villains from Sonic's rogues gallery. They might have a grand plan that requires Sonic's capture, like using his power to open a portal to a world full of chaos energy that they can then control.

A jealous rival of Inuyasha might kidnap Kagome. For example, another demon who wants Inuyasha for himself might think that by taking Kagome, he can get Inuyasha to do his bidding. This would create a lot of drama and conflict between Inuyasha and the kidnapper.

The Grimm could also be involved in an unusual way. Perhaps a new type of Grimm that has the intelligence to kidnap. They might be working with a human or Faunus villain who has some sort of control over them, and they take the character to an unknown location where the RWBY team has to face not only the Grimm but also the mastermind behind it.

The Naraku would be a likely kidnapper. He is always plotting against Inuyasha and trying to get his hands on the Tessaiga. Kidnapping Inuyasha would be a way for him to either steal the sword or find a way to break Inuyasha's spirit so that he can no longer oppose him.

It could be a jealous rival of the spirit animals' owners. This person might be envious of the special bond and powers that come with having a spirit animal and decides to kidnap them to spite the owners.

A secret society that believes Mycroft is a threat to their hidden agendas. They may think that by kidnapping him, they can stop him from interfering with their plans. They would likely be very well - organized and have resources to keep him hidden.

The kidnappers could be a group of hired mercenaries. Some powerful and wealthy person who has something to hide might have hired them. This person could be involved in illegal activities and Castle was on the verge of uncovering the truth, so they order the mercenaries to take Castle out of the picture.

The Joker is a likely kidnapper. He has a history of causing chaos and targeting the Bat - family. He might see kidnapping Batgirl as a way to get back at Batman or just for his own twisted amusement.

Perhaps a dark guild that has been observing Fairy Tail for a long time. They see Mirajane as a valuable asset and believe that her powers can help them in their evil plans. So they plot to kidnap her and force her to cooperate.

It could be a rival gang. They might see Ponyboy as a threat or a way to get back at his own gang. Another possibility is a deranged fan of his, someone who has an unhealthy obsession and wants to keep him all to themselves. Or it could be a group of criminals who mistake Ponyboy for someone else who has something they want.