Perhaps in the fanfic, he's under the influence of some sort of mind - controlling substance or magic. This external force could be driving him to harm himself as part of a larger, more sinister plot against him.
One possible reason could be extreme self - blame. Batman might cut himself as a form of self - punishment for his failures in protecting Gotham. For example, if a major villain caused great harm despite his efforts, he could turn that guilt inward.
The fanfic might use this self - harm as a symbol of his internal struggle. He's constantly fighting crime, but at the same time, he's fighting his own demons. The act of cutting himself could be a physical manifestation of that internal battle between his sense of justice and his own psychological issues.
In such a fanfic, one possible reason could be extreme depression. Maybe he faced overwhelming losses like the death of his closest friends and felt he couldn't go on. Another reason might be that he was under some kind of dark magic influence that made him lose his will to live.
One possible reason could be extreme despair. Maybe he faced some overwhelming challenges or betrayals that made him feel there was no way out. For example, if he lost all his friends and felt completely alone in the world of the fanfic.
One possible reason could be the intense pressure he faces in the wizarding world. He's constantly under the scrutiny of his family's expectations, especially being a Malfoy. The Dark Lord's influence and the fear of not living up to the family's pure - blood ideals might push him to such a dark place. In fanfiction, authors often explore the internal turmoil of characters, and Draco's situation is ripe for this kind of exploration.
One possible scenario could be that Batman sacrifices himself to save Gotham from a nuclear bomb. He uses his Bat - plane to fly the bomb far away from the city, knowing he won't be able to make it back in time. Another could be that he gives himself up to a powerful villain like the Joker in order to protect his allies. The Joker might demand Batman's life in exchange for not harming Robin and Commissioner Gordon.
You could look for fanfics about Percy's training and how he becomes stronger. For example, there might be some where he learns new skills or magic.
One possible interpretation could be that it's exploring a very dark and out - of - character moment for Harry. Maybe it's a way to delve into the extreme stress or emotional turmoil he might be facing in a non - canon, fan - created scenario. However, self - harm is a very serious topic and this type of fanfiction should be handled with great care.
One reason could be that Batman is written as being too self - absorbed in the fanfic. He might be so focused on his own mission that he doesn't want the distraction or responsibility of taking in Robin.
One possible reason could be extreme despair. Maybe in that fanfic's alternate universe, Harry has lost all his friends and loved ones in a very tragic way, like a second wizarding war that was far more brutal and unforgiving. He might see no way out of the emotional pain and thus choose to end his own life.
There may be some dark or angsty fanfics with such a concept, but self - harm themes are quite disturbing. In the 'Harry Potter' universe, this would be a very uncanonical and concerning take. It might explore a very different, perhaps depressed version of Harry Potter going through extreme emotional distress and using self - harm as a way to cope, but this goes against the overall spirit of the original series.