Well, Bellatrix is a very unpredictable character. In this fanfiction scenario, she could react with glee. Since she's on the side of the Dark Lord, she might think that Harry's abuse has made him more vulnerable. She could also be curious about who would dare to abuse 'the Boy Who Lived'. However, she might also be angry that someone else has been causing harm to Harry when she believes that's her Dark Lord's prerogative.
She might be horrified and immediately take steps to protect Sirius. For example, she could confront the abuser or report it to the proper authorities within the wizarding world.
In this fanfiction scenario, the order's reaction would be complex. They are a group dedicated to fighting against the dark forces, and Harry is an important figure. When they find out he's been abused, they'd first ensure his safety. They could move him to a secret location, perhaps a safe house that only a few trusted members know about. Then, they'd start looking into the root cause of the abuse. Was it related to the ongoing battle against Voldemort? Were there traitors within their midst? They'd also need to consider how to handle the situation publicly, as Harry is somewhat of a public figure in the wizarding world. Their main goal would be to not only protect Harry but also make sure such abuse doesn't happen again to anyone else in their community.
Snape's reaction could be quite mixed. On one hand, he might be angry at Dumbledore for not doing more if he knew about the abuse. He may also feel a strange sort of empathy towards Harry. After all, Snape himself had a difficult childhood. So, he could start to be a bit more lenient with Harry in his classes and try to subtly offer support.
Well, in some fanfictions, Voldemort might see Harry as a tool to be used against his abusers. He could use this knowledge to manipulate Harry into joining his side, thinking that he can offer protection or revenge against those who have wronged Harry.
She might be shocked and feel a great deal of sympathy for Percy. She could immediately try to comfort him and assure him that he's safe now.
In the fanfiction, if Ron finds out Harry is abused, it's a complex situation. Ron's reaction would be multi - faceted. Emotionally, he'd be a mess. He loves Harry like a brother. He might feel guilty for not noticing earlier. Ron would also start to view Harry in a new light, with more compassion and understanding. He would use his Weasley family connections to find resources or help for Harry. Maybe he'd ask his mother for advice or even get his older brothers involved if the abuse was from a powerful source within the wizarding world.
In the fanfic, Snape's reaction could be multi - faceted. He might start by investigating the abuse more deeply. He could use his skills as a Potions master and a former Death Eater to find out who is behind the abuse. And then, he might take steps to ensure Harry's safety. This could involve enlisting the help of other teachers or even trying to get Dumbledore more involved. He may also start to teach Harry some extra skills or give him potions to help him deal with the emotional and physical trauma of the abuse.
Well, in a number of these fanfictions, Draco has a very emotional reaction. He may be angry at himself for not realizing it sooner. His reaction can also vary depending on his relationship with Harry prior to the discovery. If they were enemies before, his discovery might lead to a complete shift in his attitude. He could start to see Harry in a new light and do whatever it takes to make sure Harry is no longer in harm's way. He might even change his own behavior and values in the process of helping Harry.
He might be shocked at first. Since Lucius is a complex character, he could initially see it as a weakness in Harry that he could potentially use to his advantage in the wizarding world's power games.
Draco's reaction could be complex. He has been brought up in a certain environment where showing weakness is not acceptable. But when he discovers Harry is abused, he may find it difficult to ignore. He might start by being a bit standoffish as he processes this new information. However, deep down, he might feel a growing empathy for Harry. His actions could range from small gestures of kindness, like leaving a potion that could help heal Harry's wounds secretly, to gradually becoming more open about his concern and trying to get Harry away from the source of abuse. This discovery could be a turning point in their relationship, leading to a deeper understanding and connection between them.