There might also be characters that are minor in the original but become more prominent in the fanfiction. They could be given more complex personalities and important roles in the 'gloaming glee' story.
One idea could be exploring the backstories of the characters in more depth. Maybe there are hidden pasts that influence their actions in the 'gloaming glee' world.
Maybe there is an older character who is reminiscing about the past. This character could be the central figure, and then there could be younger characters around them, such as grandchildren. The interactions between these generations could be an important part of the story, especially if the gloaming is used as a backdrop for the transfer of memories or family stories.
I don't have enough information to know who the main characters are. It could be a young hero or heroine exploring the gloaming world.
Typically, the substitute teacher would be one of the main characters. They are likely to be the central figure around which the story revolves. And then, some of the students from the 'Glee' club would also be main characters. For example, characters like Rachel, Finn, or Kurt who are very prominent in the original 'Glee' series. Their interactions with the substitute would form the core of the story.
It could be some of the well - known characters from 'The Empire' who take on new roles in the context of the Glee club. Maybe Lucious Lyon could be one, bringing his strong - willed and often controlling personality into the club and causing some chaos.
Since it's a Glee fanfiction, it would likely include characters like Rachel Berry. She's often torn between her big dreams (her head) and her feelings for her friends and Finn (her heart).
The main characters are Finn and Rachel. Finn is often portrayed as a bit of a jock with a big heart, and Rachel is the extremely ambitious and talented singer. In the context of the pregnancy fanfiction, they are the couple facing the life - changing event of having a baby.
Mr. Schuester from Glee could be a main character too. He could be the one who tries to bring the two groups together, seeing the potential in the Glee club and Supergirl working as a team. His role as a mentor in Glee could be extended to Supergirl as she tries to navigate the more complex aspects of human relationships and teamwork in this crossover fanfiction.
I don't know for sure as I haven't read it. But it could be the main characters from 'glee' like Rachel, Finn, Kurt, or Santana. Maybe it focuses on one of them in a'stuck' situation.
The children of Rachel and Finn could be main characters. Maybe their son or daughter inherits Rachel's amazing singing talent and Finn's charm. They could struggle with living up to their parents' legacy in the glee club.