Perhaps the dog was actually a cursed form of someone Harry knows or will know in the future. After the attack, as Harry recovers, he starts noticing strange behavior from certain people. This could lead to a sub - plot where Harry is trying to figure out who the dog really was. Meanwhile, his relationship with those around him might change. Some people might be more sympathetic towards him because of the attack, while others might think he's overreacting. All these things can add depth to the fanfiction story.
One possible plot development could be that Harry develops a fear of dogs. This fear might then become a character trait that affects his actions in other situations. For example, he might be hesitant to enter certain areas where he suspects dogs could be present. Another development could be that the attack was not accidental. Maybe there's a dark wizard using the dog as a tool to harm Harry, and this discovery could lead to a whole mystery-solving adventure for Harry and his friends.
The attack could lead to Harry having to stay in the hospital wing for a while. During this time, he might have strange dreams or visions related to the dog or the event. This could be a sign of some deeper magic at work. It could also be a way for the author to introduce new magical creatures or spells that are used to heal him. And his friends, like Hermione and Ron, could be by his side, trying to cheer him up and also figure out why the dog attacked him.
Harry might react with fear. He could be traumatized by the experience and be constantly on edge, jumping at the slightest sound. This fear could make him more cautious in general.
Well, it could be that there's a misunderstanding. Maybe some Gryffindor students think Harry has done something wrong, like he's been framed for a crime in Hogwarts. So they turn against him in anger and attack him. But later they find out the truth and feel really guilty.
Well, perhaps they could become friends quickly. Bill might introduce Harry to some interesting magical things he hasn't seen before, like some unique creatures. And they could start having little adventures together around the wizarding world.
The fact that Harry is sorted into Ravenclaw could also cause a rift with some of his Gryffindor friends at first. However, as time goes on, they could come to see the benefits of his new House. Harry might introduce some Ravenclaw values like open - mindedness to Gryffindor. And his Ravenclaw housemates could also learn about loyalty and bravery from Harry. This could lead to a more united Hogwarts against Voldemort, with all the Houses working together in new ways.
The plot could involve Harry, as a dog, being found as a stray in the wizarding world. He might be taken in by Hagrid, who recognizes his special magical potential. Harry could then use his dog - like instincts to discover hidden secrets in Hogwarts, like secret passages that are only accessible to small animals. He might also form an unlikely alliance with some of the other magical creatures, like the Kneazles, and together they could foil the plans of the dark wizards.
Well, one possibility could be that they start sharing magical knowledge more often. Since they're neighbors, it's easier for Hermione to drag Harry to her place to study new spells or potions. Another could be that they team up to deal with local magical nuisances, like a poltergeist that's causing trouble in their neighborhood. And they might also end up introducing each other to their respective Muggle and wizarding families more frequently.
One possible plot development could be that Harry finally experiences a true family environment. Sirius could teach Harry more about his parents, their secrets, and the wizarding world in a more personal way. They might also face some threats together as Sirius is still a wanted man in some parts of the wizarding world. This would create a lot of tension and action scenes in the fanfiction.
In this fanfiction, Ichigo's training at a young age might be a result of a premonition of a great danger to come. A powerful shinigami takes him under his wing and starts training him in combat skills against Hollows. The training is intense, with Ichigo learning how to use his reiatsu more effectively, and also learning about the different types of Hollows and how to counter them.
One possible plot could be that Harry has some sort of post - war trauma from all the battles he's been through. The service dog could be trained to sense his panic attacks and help him calm down. For example, when he has nightmares about Voldemort, the dog wakes him up and stays by his side until he feels better.
Maybe the story could develop with Snape trying to understand why Harry is a Malfoy fan. He could start to investigate Harry's past interactions with the Malfoys and any hidden reasons behind his admiration.