In the fanfiction, it could be that Red X binds Starfire tightly as part of a game or a test. He might be testing her abilities or her loyalty to the Titans. While she is bound, she has to use her wits and her unique powers in a different way to try and free herself. This situation could also bring out a different side of Red X, where he starts to respect Starfire more as he sees her struggle and determination.
Perhaps Red X has a personal vendetta against Starfire. He binds her tightly as a way to show his dominance and to try and break her spirit. In the fanfiction, this could lead to a series of events where Starfire has to find her inner strength to escape and also to figure out why Red X has such hatred towards her. It could also involve the other Titans coming to her rescue and a big showdown between them and Red X.
One possibility could be that Red X is under some sort of mind control and is made to target Starfire. He binds her tightly as part of a plan to hold her hostage in order to get something from the Teen Titans. Maybe he wants some powerful artifact that the Titans are protecting and he thinks Starfire is the key to getting it.
There could be other characters from the DC universe that step in to save Starfire. Maybe Superman, who is known for his sense of justice, hears about Starfire's plight and decides to help. He could easily overpower Red X and free Starfire. Another possibility is Wonder Woman. She would be a great ally in this situation. With her strength and combat skills, she could take on Red X and rescue Starfire.
Well, it could start with Red X having some ulterior motive like using Starfire to get to the Teen Titans. Maybe he plans to ransom her or use her powers for his own gain. He might keep her in a hidden lair and Starfire would be trying to escape while also trying to figure out what Red X really wants.
One possible plot could be that Harry, perhaps in a search for power or knowledge, binds the succubus. But then he has to constantly battle her wiles and temptations as she tries to break free. He might use magic he's learned at Hogwarts to keep her in check.
One possible motive could be to use her as a bargaining chip. Maybe against the other Teen Titans, like Robin or Beast Boy. Red X might want something in return for her safe release.
You can try searching on fanfiction platforms like FanFiction.net or Archive of Our Own. Just use the keywords'red x kidnaps starfire' in their search bars. There might be some great stories out there that match this plot idea.
You can try searching on fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, and you might be able to find some great Starfire x Red fanfics there by using the search function.
It could be about an adventure where Red and Sticky have to tie up Starfire for some unexpected reason in the context of a fan - created story. Maybe they're trying to protect her from a greater threat by restraining her temporarily.
You can try websites like Fanfiction.net or Archive of Our Own. They have a large collection of fan - created stories, and you should be able to find some great Starfire and Red X fanfiction there.
Well, it could be that Harry, in this fanfic, discovers a way to bind the succubus familiar through some ancient magic he stumbles upon. Maybe he needs its powers for a particular task, like fighting a new dark force in the wizarding world.
The difference in their moral compasses. Red X is more likely to cross ethical lines. Starfire, with her strong sense of right and wrong, would find it hard to be under his control in his grip, as it would go against her principles.