Since I haven't read it, I can't say for sure. But it could be the tiger itself as a main character in a sense. Maybe there's a zookeeper or a hunter who also plays a significant role.
It's possible that there is a character who is the antagonist in the story. This could be someone who wants to capture or kill the tiger for personal gain, like a greedy businessman who wants to sell the tiger's parts. And then there could be a wise old man in the village who gives Harry Black advice about how to deal with the tiger and the situation.
There might be a local villager who has some knowledge about the tiger. This villager could be an important character as he or she might help Harry Black in his journey related to the tiger. Another possible character could be a scientist who is interested in studying the tiger and crosses paths with Harry Black.
It's possible that some of the minor characters from the original Harry Potter series could take on more prominent roles. For example, Neville Longbottom could be a key character. He has shown great courage in the series, and in this fanfiction, he might be one of the few who can stand up to the black wizard. Also, Professor Snape's backstory and his relationship with the black wizard could be further explored, making him an important part of the story as well.
Sirius Black's relatives would be likely characters. For example, Kreacher, the house - elf of the Black family. He could play an important role as he has a deep knowledge of the Black family secrets and the Black family manor. Also, Narcissa Malfoy, as she is related to the Black family, might be involved. She could either be an ally or an adversary to Harry depending on how the story unfolds.
I'm not sure specifically as I haven't read this novel in detail. But it might be about Harry Black's adventures related to a tiger, perhaps his encounters with the tiger in a particular setting like a jungle or a circus.
There are various owners of Black Beauty, like the kind farmer who gives it a good start in life. And also the cruel cab driver who overworks it.
There could be the mafia boss. He might be a tough and shrewd character who takes Harry under his wing at first but later becomes suspicious of Harry's actions. Another main character could be Harry's best friend in the mafia. They go through all the dangerous and exciting adventures together, and this friend might have different views on the mafia life compared to Harry.
There could be a doll collector named Alice. She might be Harry's friend or rival, always competing to get the best dolls in the story.
Well, Dumbledore would most likely be a significant character. He might be one of the few people who quickly understand the implications of Harry being a mutant. He could help Harry navigate through the challenges that come with his new identity. Additionally, there could be some mutant characters from the mutant universe who cross over into the Harry Potter world. For example, a character like Professor X could be an interesting addition, guiding Harry in understanding and using his mutant powers in a responsible way.
Maybe there's a human friend who is really curious about Harry's new situation. This friend could be constantly asking questions and trying to get involved in Harry's alien - related adventures, adding some comedic relief to the story.
There might also be a love interest for Harry. This character could be someone who is also involved in the dangerous world of assassination in some way. She or he might be a fellow assassin or someone who is on the periphery of that world but still gets drawn into Harry's life, adding a romantic sub - plot to the story.
Hermione could be a main character. She might be the one who helps Harry understand and control his gorgon powers. For example, she could research in the library to find ancient spells or potions that can suppress the gorgon - like effects when they are unwanted.