There could also be characters from the original series that interact with Harry in new ways due to his time - traveling and adopted status. For instance, Dumbledore might have a different relationship with Harry if he is adopted. He could be more of a mentor figure trying to guide Harry through the new changes in his life.
It's possible that the author might introduce some time - travel related characters, like time - guardians or beings that exist outside of normal time. These characters could either help or hinder Harry in his time - traveling adventures and understanding of his new adopted situation.
The main characters are Harry, who is used to being in the wizarding world of Hogwarts, and Selene. Selene is probably a powerful character with her own set of abilities. In the fanfic, their interactions will be the focus, as Harry adjusts to being adopted by her and they form a new kind of relationship.
One interesting concept could be how Harry's actions in the past through time travel might change the future of the wizarding world in ways he didn't anticipate. For example, if he accidentally alters the relationship between certain families, it could have a ripple effect on the balance of power.
Obviously, Harry Potter is one of the main characters. He is the one being adopted into the Greengrass family. Then, the Greengrass family members are important. There are likely to be the parents of the Greengrass family, and the Greengrass sisters. We might see Astoria Greengrass and her sister (if she has one in the fanfic). These characters will play significant roles in Harry's new life and the development of the story.
Scorpius Malfoy is another likely main character. His family's history and his own inquisitive nature would make him an interesting addition. He might be the one who discovers the time - travel mechanism. His relationship with Albus Potter could also be explored further as they embark on this time - traveling adventure together, and his views on his family's past actions could change during the journey.
Harry could be a young, orphaned boy with a lot of potential. He might be a bit naive at first but has a kind heart. Reno could be an older, more experienced person, maybe a warrior or a survivalist. He has seen a lot in his life and has a tough exterior but a soft spot inside.
Lily Luna Potter might also be a main character. She has a strong personality and her own set of skills. Her presence in the time - travel plot could bring a different perspective, especially when it comes to interacting with the female characters from the past.
Obviously, Harry Potter and Andromeda Tonks are the main characters. Harry is the well - known hero of the wizarding world, and Andromeda, as a member of the Black family who has broken away from their dark traditions, brings her own unique perspective and backstory to the time travel story.
Obviously, Harry Potter is the main character. Then there would be the wolves who adopt him. There might be an alpha wolf that acts as a sort of leader and protector for Harry. And perhaps there could be other magical creatures in the forest that interact with Harry and the wolves, like centaurs or unicorns.
Harry is the central character as the one being adopted. The Castle family members, such as the parents in the family, are main characters too. There could also be other family members like siblings or grandparents who interact a lot with Harry and shape his new life in this fanfiction world.
Obviously, Harry Potter is one of the main characters as the story is about him being adopted. Sirius Black could also be a main character, as he is part of the Black family and might play a big role in Harry's new life.