Harry could put himself in great physical danger. Voldemort might not be willing to help without exacting a high price, like Harry's own life or his magic. And even if Voldemort does seem to offer help, it could be a trap to harm Harry.
Perhaps Harry has a plan to outwit Voldemort in the long run. By seeking help, he can get closer to Voldemort, understand his weaknesses better, and then use that knowledge against him. It's a risky but potentially effective strategy, like a spy infiltrating the enemy's camp.
The most obvious consequence would be that Voldemort would likely betray Harry. Voldemort is evil at his core, and he would probably use this opportunity to harm Harry or gain more power. For example, he could steal Harry's magic or use him as a pawn in a new scheme.
Well, in many fanfictions, Harry might use his knowledge of hidden places in the wizarding world like the Room of Requirement. He could also rely on the help of his friends. For example, Hermione might use her vast knowledge of spells to create a hiding place or a protective charm. And Ron could be there to offer physical protection if needed.
The wizarding world might be in shock. People who have always seen Voldemort as the ultimate evil would be confused. They would have to re - evaluate their views on Voldemort. Harry, on the other hand, would be in a very strange situation. He might be distrusted by some of his friends who think he has made a deal with Voldemort.
There could be various consequences. Firstly, a cease - and - desist order might be issued, forcing the seller to stop selling the fanfiction immediately. Secondly, the seller may have to pay damages. Since 'Harry Potter' is a very valuable brand, the damages could be substantial. And thirdly, in some cases, there could be criminal charges if the infringement is severe enough, although this is less common in cases of fanfiction sales.
One challenge could be betrayal. There might be some so - called allies who are secretly working for Voldemort. Another is the lack of resources. If he is constantly on the run, he may not have access to enough food, water or magical supplies. And he has to be constantly vigilant against dark magic spells that Voldemort might send his way.
One problem is that it may distort the characters. Harry Potter and Voldemort have very defined characters in the original series. A 'lemon' fanfiction may change their personalities in inappropriate ways just to fit the adult - themed plot. Another issue is that it can make the fandom seem less family - friendly. The Harry Potter fandom has a lot of young fans, and this type of fanfiction can be off - putting to them.
The wizarding world would likely be in a state of shock and then celebration. People would start to see Azkaban in a new light, perhaps no longer as just a place of horror but also as the site where the great evil was finally vanquished.
One potential consequence could be disrupting the natural balance of water - based magic. If he teleports too often or without proper control, it might cause ripples in the magical ecosystem of water bodies. Another consequence could be attracting unwanted attention from water - dwelling magical creatures. They might see his teleportation as an intrusion or a threat.
The wizarding economy would be in chaos. Gringotts is the central bank of the wizarding world. Its destruction would mean that people's savings, vaults, and all the financial transactions would be disrupted. Wizards and witches would lose their trust in the financial system.