There could be a young unicorn named Starlight. He might be a brilliant but overconfident student who Twilight has to guide. Another character could be a pegasus named Rainbow, who is always getting into trouble and Twilight has to keep in line.
Her friends like Pinkie Pie, Rainbow Dash, Applejack, Rarity and Fluttershy are likely to be main characters. Pinkie Pie might bring her usual cheer and parties to celebrate Twilight's new form. Rainbow Dash could be both impressed and a bit competitive, trying to keep up with Twilight's new abilities in her own way. Applejack would offer her down - to - earth advice and support. Rarity might be excited to create new outfits for Twilight as an alicorn. And Fluttershy would be there with her gentle nature, providing a calming presence.
Well, it could be that the fanfic is set in an alternate universe where Twilight, instead of being a princess, is a headmaster. The story could revolve around the relationships she forms with the students. For example, she might take a special interest in a misfit student and help them find their place in the school. There could also be a sub - plot about a rival school trying to undermine Twilight's school, and she has to use her wisdom and magic to protect it.
One of the main characters could be Twilight Velvet's mate. He would play an important role in the story, perhaps being there for her during the pregnancy and helping with the care of the foal. Another character could be Twilight Velvet's mother. She might offer her own experiences and wisdom about raising a foal.
I'm not entirely sure as it's a fanfic, but it could include the main characters from the Twilight series like Bella and Edward. They might be involved in the events around the twilight lagoon, perhaps exploring it or having some kind of encounter there.
There could be students. Students often play important roles in a school - based visual novel. They might be the ones causing trouble that the headmaster has to deal with, or they could be the ones with great potential that the headmaster wants to nurture.
Edward is often involved. Since he's so close to Twilight, he would be there to support her or sometimes be a source of conflict as he tries to help in his own way but might not always understand what she's going through. Bella's family, like Charlie, could also be main characters. Charlie might notice the changes in Twilight and try to figure out what's wrong. And then, her vampire friends like Alice could play a significant role. Alice might use her ability to foresee things related to Twilight's PTSD, either to help or sometimes make things more complicated.
The other members of the werewolf pack could be important characters. They are Jacob's family in a way, and they would surely be affected by Jacob's state if he's 'too heavy'. For instance, Sam, as the alpha, might try to guide Jacob out of whatever is making him this way.
Fluttershy might be a key character. Her gentle and kind personality could have a big influence on Twilight's daughter. The daughter could learn about compassion and caring for animals from Fluttershy. And of course, Rarity could be in it too. Rarity could help the daughter with her appearance and self - confidence, perhaps creating some beautiful outfits for her.
The main characters could also include some of the more powerful or unique characters from each series. In Harry Potter, Dumbledore with his great wisdom and magical power might play a key role. He could be the one trying to figure out how to deal with the Twilight - related elements in this crossover. In Twilight, the Volturi, with their control over the vampire world, could be main characters. Their actions and decisions would likely have a big impact on the story as they interact with the wizards. Additionally, characters like Jacob from Twilight, with his werewolf nature, would add an interesting element when interacting with the werewolves in Harry Potter (if any are included in the fanfic).
Princess Celestia is often included. She is an important figure in Canterlot and could play various roles in the wedding fanfiction. For example, she might be the one giving Twilight advice or overseeing the wedding arrangements. Then there's Rainbow Dash. As Twilight's friend, she could be involved in some exciting flying stunts during the wedding festivities or helping with last - minute preparations. Pinkie Pie is also a common character. She would surely be in charge of the party - planning aspect of the wedding, making sure there are plenty of delicious treats and fun games.