How could Harry Potter survive if he lives in the Forbidden Forest in fanfic?

Well, he might have a lot of encounters with magical creatures. Maybe he'd befriend some centaurs or learn the secrets of the forest from them. He could also face more hidden and dangerous dark magic that lurks in the forest.

Maybe Harry discovers a hidden magical community in the forest. He could learn new spells from the forest creatures and use them to protect Hogwarts later.

He might encounter magical creatures that are not known to most wizards. For example, he could meet a rare breed of unicorn or a group of centaurs who take him under their wing and teach him their ways of magic and life in the forest.

She would use her extensive knowledge of magic. For food, she could use magic to conjure or transfigure things. She might also forage for non - magical plants that are safe to eat and use her knowledge of Herbology to identify them.

His relationship with Hogwarts students would be very different. Instead of growing up with them, he would be an outsider. When he finally meets them, they might be in awe of him or even a bit afraid because of his different upbringing.

Hermione could be one. She might come to the forest to check on Harry and end up staying to study the unique flora and fauna which have magical properties. Another could be Hagrid. He loves all kinds of creatures and the forest is full of them, so he could visit Harry often and bring him supplies.

To survive in Azkaban, Harry would need to keep his mind active. He could recall all his happy memories to counter the Dementors. His knowledge of magic could also be useful. For example, he could try to create some protective spells around his cell. And he might get some unexpected help from the guards or other mysterious forces within the prison.

I recommend the novel "The Most Mad Immortal of Rebirth", which tells the story of the black-haired, black-eyed protagonist, Wu Zheng, who returned to the top of the Nine Regions after his rebirth and swept the world with invincible posture. The main character was once the enemy of ten thousand people on the battlefield and was saved by an immortal. However, when the immortal technique was completed, he was plotted against by his senior brother and sister and was reincarnated. In this life, he had been reborn. He was no longer humble, no longer confused. With an invincible posture, he once again reached the peak of the Nine States. He was the main character with black hair and black eyes, and was known as the Demon King. I hope you like my recommendation, Mwah~

Maybe it's a powerful and reclusive wizard who has chosen to make the forest his domain. He has mastered forest - related magics that are unknown to most wizards. He has made a pact with the forest itself, becoming its protector and ruler, and thus is known as the Lord of the Forest.

Well, Harry Potter is a very resourceful character. In Muggle prison, he'd first assess the situation. He'd figure out the daily routines, the power dynamics among the inmates and the guards. He could use his magic to create small advantages, like making food taste better or getting a warmer blanket at night. He'd also use his charm and charisma to make allies among the inmates. If there were any bullies, he'd stand up to them, just like he did against Draco Malfoy at Hogwarts. And he'd be constantly looking for an opportunity to break out, using his knowledge of magic and his ability to solve puzzles.