He might become more independent. Without the Dursleys, Harry would have to fend for himself. He could start to discover his true powers faster as he no longer has to hide his magic in the Dursley household. For example, he could practice magic freely and develop his skills more quickly.
There could be a sense of loss and confusion at first. Harry has known the Dursleys as his family, albeit a horrible one. So, being abandoned by them would still be a shock. He might question his own worth and where he belongs in the world, but eventually, this could lead to a journey of self - discovery.
His relationships could be affected. Hermione and Ron might have to take on more of a caretaker role, which could change the dynamic of their friendship. Also, he may face discrimination or pity from other students at Hogwarts, which could further isolate him. And in terms of romantic relationships, his self - esteem due to his crippled state might make him less likely to pursue someone like Ginny.
It could also be that Harry himself is so traumatized by the war that he isolates himself. He might push people away, thinking that he's a danger to them. As he withdraws, others might misinterpret it as him not wanting their company and gradually abandon him.
Some fanfictions might depict that the wizarding community might see her as a hero. However, others could show that she faces backlash from some conservative wizards who think she overstepped her bounds. They might try to isolate her at Hogwarts or spread rumors about her. But her friends like Harry, Ron and Hermione would surely support her through it all.
One consequence could be that Harry becomes withdrawn. He's so used to the abuse that he doesn't trust people easily. He might have nightmares often, reliving the moments of abuse. For instance, if Vernon has hit him before, he could have flashbacks in his sleep.
He could become very withdrawn. Since the Dursleys are constantly abusing him, Harry might start to avoid people and isolate himself even more. He may lose his self - confidence and feel that he is not worthy of love or respect.
They would likely face severe punishment from the wizarding world. The Ministry of Magic would not tolerate such blatant abuse of a wizard, especially one as important as Harry.
Well, in this kind of fanfiction, it might be that Harry is adopted by a wizarding family from another country. This new family could introduce him to different magical cultures and traditions. He could learn spells and magical techniques that are not known in the British wizarding world. Also, he might start to explore his own identity without the shadow of the Dursleys. He could find out more about his parents from this new family's perspective and gain a new understanding of his place in the wizarding world.
After saving Harry, Snape may have to deal with a lot of mistrust from some people in Hogwarts who don't understand his motives. However, he might also start to form a closer bond with Harry, which could change the whole dynamic between them. This new relationship could lead to some unexpected alliances and enmities within the wizarding world. And if the Dursleys were to try and retaliate, Snape would have to constantly be on guard to protect Harry from any potential harm they could cause.
Well, if we consider this in the context of fanfiction, it might be a very extreme exploration of the 'dark!Harry' trope. However, it goes against everything Harry represents in the original series. Firstly, the Dursleys, despite their mistreatment of Harry, are Muggles and killing and eating them is an inhumane act. This would cause a huge uproar in both the Muggle and wizarding worlds. Harry would be seen as a monster.
Dumbledore could be a savior in this fanfiction. He has the power and the wisdom to step in and help Harry. He might have been waiting for the right moment to remove Harry from the Dursleys' influence. Also, there could be a new character, like an old and powerful wizard who has been in hiding but senses Harry's distress and comes to his aid. This wizard could have some unique magical abilities that can protect Harry and help him grow into a powerful wizard himself.