Who could be the main character in 'Harry Potter and the Poisonous Snake Fanfiction' other than Harry Potter?

It could still be Harry Potter himself. He has a history of facing dangerous creatures and dark magic, so it would be natural for him to take on the challenge of the deadly snake.

Neville could be a great main character for this kind of fanfiction. He's not as confident in potions as some others. So, an accident where he creates a potion that makes all the plants in the Hogwarts greenhouses go wild and start to overgrow and take over parts of the castle would be an interesting story. He would then have to use his knowledge of Herbology to try and control the situation.

Hermione could be one of the main characters. She would be very helpful with all her knowledge of spells and magic theory. She could assist Harry in planning the layout of the village and ensuring that everything is in order.

Another option could be a new character. A transfer student, perhaps, who is really a Slytherin at heart but is placed in Gryffindor by mistake. This character then has to keep up the pretense of being a Gryffindor while dealing with their true Slytherin nature.

It could also be a snake from the Forbidden Forest. There are many unknown and mysterious creatures in there. A snake from that forest might be more in tune with the natural magic of Hogwarts. Harry, being the curious and kind - hearted person he is, might come across it during one of his adventures in the forest and start a friendship with it.

It could be Nagini. Even though in the original series she was more of a servant to Voldemort, in the fanfiction, she could have a different personality and form a bond with Harry.

Maybe it's an anonymous gift from someone who has been observing Harry. This person could be a former student of Hogwarts who has a special connection to snakes and sees that Harry has a kind heart and would take good care of the snake. So they leave the snake for Harry to find with a simple note that just says 'For Harry Potter'.

Ron could also take on the role of the main character. He has his own brand of courage and loyalty. He could be the one who, in a moment of desperation, unlocks the power that is Voldemort's bane. For example, he might use his family's old magic artifacts in a new and unexpected way.

Hermione could be a main character. She might be initially skeptical about Harry singing muggle music, but then she gets interested in the cultural aspect of it and starts researching the history of the muggle music Harry likes.

There could be an original character who is a descendant of the Uchiha that somehow ends up in the wizarding world. This character could teach fem Harry Potter about the Uchiha ways. Also, Dumbledore could play a role as he always encourages Harry's exploration of different knowledge, and he might be curious about the Uchiha knowledge that Harry is so interested in.