The other characters could have a range of reactions. For example, those who were close to him might feel betrayed. They might have thought they knew him well, but his getting caught reveals a whole new side. On the other hand, characters who were his enemies might feel a sense of satisfaction. They might use his capture as a way to further their own agendas, like getting more power or influence in the fanfiction world.
Some characters might be shocked. They could never have expected Dexter to be involved in such situations.
In some cases, when Dexter gets caught, the people who catch him might try to rehabilitate him. They could think that there's still some good in him and attempt to change his ways. However, Dexter might resist this change as his nature is deeply ingrained. This could lead to a power struggle between him and those who want to reform him, creating a lot of drama and tension in the fanfiction story.
Some characters might be very worried and rush to his aid. Others could see it as an opportunity to gain power or influence in his absence.
Kagome usually gets very worried. She'll immediately try to use her spiritual powers to heal him if she can. If not, she'll search for herbs or other ways to help. Miroku would likely offer his support in a more practical way, like finding a safe place for Inuyasha to rest. Sango might be on guard, making sure that no more enemies take advantage of Inuyasha's weakened state.
Harry would probably be extremely worried. He'd immediately rush to her side, trying to figure out how to help. Ron, on the other hand, might be in a bit of a panic at first but then would do whatever he could to protect her while waiting for help. Hagrid might bring some of his home - made remedies, thinking they could work on her injury.
Simon might be in a bit of a panic. Since he's her friend and also not as used to the dangerous situations as the other Shadowhunters. He'd try to do whatever he can to help, like getting help from more experienced Shadowhunters or trying to comfort Clary while she's in pain.
Jay would probably be very vocal. He'd be shouting for help and freaking out a bit. Kai would be angry at whoever or whatever hurt Zane and be ready to fight back immediately. Lloyd, being the leader, would try to stay calm on the outside but be very worried inside and start coming up with a plan to help Zane.
Thorin would probably be very concerned. Since Bilbo has become an important part of their group, Thorin might feel responsible for his safety. He could order the others to help Bilbo immediately and make sure he gets proper care.
Natasha Romanoff would likely be very protective. She and Clint have a long - standing friendship and partnership. So, she would probably be by his side immediately, using her skills to tend to his wounds if possible, and vowing revenge on whoever hurt him.
Piper might be very worried and use her charmspeak to try and keep Jason calm. Leo could use his mechanical skills to build something to help with Jason's injury, like a makeshift stretcher or a device to monitor his condition. Annabeth would probably come up with a strategic plan to get Jason to safety and figure out how to heal him.
When Hazel gets hurt on the Argo 2 in fanfiction, it's a big deal for the other characters. Each of them has their own way of reacting. Jason, for instance, would use his leadership skills along with Percy to keep the crew in order. Nico, Hazel's brother, would be extremely worried and might even use his powers to try and find a way to heal her if possible. The whole crew would come together, their individual relationships with Hazel and each other playing a role in how they respond to her injury. They would support her both physically and emotionally, showing the strong bond among the characters on the Argo 2.