In many fanfictions, Severus Snape could be involved. He has a deep knowledge of dark magic, so he might be either trying to prevent the basilisk ritual from being misused or he could be lured by the power it offers. Dumbledore is also a likely character. He would be the one to guide the students or other characters in dealing with the implications of the basilisk ritual. And of course, Tom Riddle (Voldemort) could be a key figure if the ritual has something to do with his rise to power or his plans for the wizarding world.
Neville Longbottom could be a character in some basilisk ritual fanfictions. He has shown great courage in the original series, and in a fanfiction, he could be the one who unexpectedly has a connection to the basilisk ritual. Maybe his family has some long - forgotten knowledge about it. Luna Lovegood might also be involved. Her unique perspective on magic could help in understanding the strange and dangerous aspects of the basilisk ritual.
Hermione would probably be involved. She's always by Harry's side, and she might be researching ways to help Harry tame the basilisk. Maybe she finds some useful spells or information in the library that gives Harry an edge.
Obviously, Harry Potter himself is usually one of the main characters. He is often the one who has to face the basilisk in these fanfictions.
Well, in some fanfictions, the basilisk ritual could be tied to a prophecy. A young wizard might be the key to either stopping or starting the ritual. This could lead to a race against time as the dark forces try to complete the ritual while the good side tries to prevent it. There could also be a plot where a character is possessed by the essence of the basilisk during the ritual and their friends have to find a way to save them.
Hermione Granger is also a common character. Given her love for knowledge and her skills in magic, she would likely be researching the best spells and magical theories to make the terraforming successful. She might be the one to find ancient spells that are crucial for the process.
In many expelled Harry Potter fanfictions, the Weasley family as a whole gets involved. Molly Weasley would be worried sick about Harry and would be cooking up plans to get him back. Fred and George might use their prank - making skills to expose the truth behind the expulsion. Ginny, being Harry's love interest in the original series, would be actively involved in trying to clear his name. And don't forget about the Hogwarts professors. McGonagall would probably be torn between following the rules and believing in Harry.
Harry Potter himself is often a central character. He might be shopping for new school supplies at Flourish and Blotts or looking for a new broomstick at Quality Quidditch Supplies. His friends, like Hermione and Ron, usually accompany him. Hermione might be more interested in books and rare magical artifacts, while Ron would be eyeing the latest Quidditch gear.
Mrs. Weasley is a very likely character. She's an expert at cooking and baking in the normal wizarding world, so in fanfiction about magical bakes, she could be teaching the younger characters how to make special bakes. Hagrid might also be involved. He could bring in some really strange ingredients from the Forbidden Forest, like giant acorns, to be used in the bakes.
Hermione Granger is often involved. In some fanfictions, she discovers hidden conspiracies within the Hogwarts library. For example, she might find a book that reveals a plot by some of the older pure - blood families to keep certain magical knowledge from half - bloods and Muggle - borns.
Harry Potter is the central figure for sure. His friends, Ron and Hermione, are likely to be important as they usually are in Harry Potter stories. In addition, there could be antagonists who are either against Harry because of his strange origin or are trying to use his basilisk - related powers for their own evil purposes. There might also be some sort of basilisk - like creatures or characters with a connection to basilisks that play a significant role in the story.
It could be an original character created by the fanfiction writer. Maybe a young wizard who stumbles upon the dragon ritual by accident and becomes the central figure in the story.