One possible plot could be that Anzu is constantly trying to break free from Dark Bakura's mental hold. She might have to face her inner fears and insecurities that Dark Bakura is using against her. Maybe she has to find a way to resist his dark magic and manipulations.
The main characters are surely Anzu and Dark Bakura. But there could also be other characters from the original series who might play supporting roles. For example, Yugi could be someone who tries to help Anzu break free from Dark Bakura's grip. Or perhaps some of the other friends like Joey or Tristan might also be involved in some way, either by being directly affected by Anzu's situation or by trying to find a way to rescue her.
Well, it's hard to say without reading it, but it could be Yugi. Yugi often plays an important role in stories related to Marik as he has a connection to the Millennium Puzzle and is a powerful duelist. He might be involved in trying to help Anzu break free from Marik's dark half grip.
Since I don't have access to this fanfiction, it's hard to say for certain. However, if we think about common themes in similar stories, Anzu might be struggling against Marik's dark side in a battle of wills. Maybe she has to make difficult choices that will either save herself and others from Marik's dark half or risk being consumed by it. It could also involve her trying to understand the root of Marik's dark transformation and using that knowledge to her advantage.
Anzu would probably be scared at first, but then she'd likely start to think of ways to escape. She's a brave character, so she wouldn't just sit there and accept her fate.
Another aspect to consider is Dark Bakura's motivation for capturing Anzu. Is it simply for revenge against Yugi? Or does he have a more complex plan? He might try to extract secrets from Anzu about Yugi's strategies in duels. And Anzu, being a strong - willed character, would likely not give in easily. This could create a great deal of tension and conflict in the fanfiction.
Anzu could use her wits. If she can find a moment when Bakura is distracted, she might be able to run away. Maybe she could create a diversion, like knocking over something noisy to draw his attention and then make a break for it.
Well, it could be about Kari being physically restrained by Gennai in a dark place, perhaps a dungeon. She might be struggling to break free, both physically and mentally, while Gennai has some evil intentions towards her.
The title '18 struggles in cell grip fanfiction' is rather mysterious. It could imply that there are 18 distinct types of turmoil or problems within a setting that has to do with being in a cell - like confinement. This could be in a science - fiction setting where a cell might be a containment unit for some sort of experiment, or in a more traditional sense like a prison cell. The 'fanfiction' part suggests it's a work created by a fan, building on an existing universe, but again, without reading it, we can only guess what those 18 struggles might be.