I think it'll offer a thrilling plot. Since it's part of the 'Death in Paradise' series, it may involve complex relationships between the characters. The main character, perhaps a detective, will likely use their wits to figure out who the culprit is. It could also give us more insights into the local culture of the paradise setting.
Well, Bruce could leave in fanfic for the sake of self - discovery. He's constantly struggling with his identity as Bruce and as the Hulk. Fanfic authors might write him leaving to find a place where he can better understand himself without the distractions and pressures of the Avengers team.
It's likely about mysteries and crimes set in a paradise - like location. Maybe it involves detectives solving strange murders while surrounded by beautiful scenery.
It could be about a mysterious death that occurs in a seemingly idyllic place, perhaps a tropical paradise. There might be complex characters like the detectives who are trying to solve the case, and it may involve secrets and lies within the community of that paradise.
In some fanfictions, Regina might leave Emma for Robin because of a deeper emotional connection she feels she has with Robin. Maybe she sees in Robin something that she feels is lacking in her relationship with Emma, like a more traditional form of love or a different kind of understanding.
He could leave because he doesn't fit in. Naruto is all about the ninja way, with its own code of honor and fighting style. The Justice League's superhero culture is just too different.
In some fanfiction, Peter Parker might leave the Avengers because he feels out of place. Maybe he realizes that his style of heroism doesn't quite fit with the more organized and sometimes bureaucratic way the Avengers operate. He could also leave due to personal reasons, like wanting to focus more on protecting his local neighborhood in Queens rather than getting involved in global Avengers - level threats.