One challenge could be the state of the body. If it has been damaged or decomposed, it would be difficult to identify. Another might be the lack of proper identification tools or information at the scene. Maybe there are no fingerprints available or dental records are missing.
Castle might become obsessed with finding the truth about what happened. His writer's mind would start formulating theories and he would stop at nothing to get justice for Beckett, which could put him in dangerous situations.
He would likely feel extreme shock. Just the sight of her body could send his mind into a tailspin. He might also be in denial at first, not wanting to believe that it's really her.
It might start with Castle getting the news of Beckett being in a dangerous situation, like a crime scene or an accident. Then he rushes to the location where her body is supposed to be.
He could become more withdrawn. Losing Beckett like that would make him hesitant to let people in again. He'd be more guarded, fearing another loss.
Castle could initially deny it's her. He'd look for any sign that it's not Beckett, checking for details that are off. As he realizes it is her, he'd break down, crying uncontrollably. His world would shatter because she was such an important part of his life, and he'd be filled with regret for any unsaid words or things they didn't do together.
Since it's a fanfic, it could go in many different directions. It could be a tragic story where Castle succumbs to cancer, or it could be an inspiring one where he overcomes it. It might also be a story that focuses more on the emotional and psychological aspects of having cancer, such as the fear, the anger, and the acceptance. It could also be set in a particular fictional universe that the original Castle concept belongs to, and the cancer plot could be intertwined with the existing storylines and characters from that universe.
Well, usually when Castle leaves Beckette in such fanfics, it causes a lot of emotional turmoil for both. There could be moments of self-reflection for Beckette, and maybe Castle realizes his mistake and tries to come back. It all depends on the author's imagination!
An 'arranged castle fanfic' is likely a fan - created fictional story that involves some sort of arranged situation within the setting of a castle. For example, it could be an arranged marriage between two characters in a castle, or an arranged alliance. Fanfic, short for fan fiction, is written by fans of a particular work, often a book, movie, or TV show, and they use the existing setting and characters to create their own stories.
It could be a vengeful criminal that they put behind bars. This person has escaped and wants to get back at them, so they engineer their disappearance. Maybe they have a whole elaborate plan to torture them in some remote location.
The style of the novel can be a hurdle. Novels often have a distinct writing style, like flowery language or a very concise style. Maintaining that same style in translation is not easy. Translators need to be creative to find the right words and phrases in the target language that match the original style.