Padme herself is obviously a main character. She is the one giving birth after all. Her baby, which could be Luke or Leia in the Star Wars context, is also an important part, even if not fully developed yet at the time of birth.
Obviously, Clary herself is central. Then there's Jace, her love interest. He would be very involved, probably being there for her throughout the pregnancy and during the birth. Simon might also be there. As Clary's best friend, he would offer his support in his own way, perhaps with some comical moments to lighten the mood.
In Pokemon birth fanfiction, Misty can be a popular character. She has a strong connection with water - type Pokemon, and she could be involved in the birth of a water - type Pokemon, perhaps using her knowledge of water to create a suitable environment. Professor Oak is also a character that often shows up. His vast knowledge of Pokemon would make him a valuable asset during a Pokemon birth. And Pikachu, as Ash's most famous Pokemon, might also be part of the story, either as a helper or just being curious about the new - born Pokemon.
Hermione would probably be involved. She's always been there for Harry in the original series, so in this fanfiction, she might be the one trying to find a way to reverse the situation or help Harry through the process. She's smart with potions and magic, so she'd be a key character.
Another possible character could be a secret supporter of Anne Boleyn. This person might be trying to find a way to get word out about her situation or even plan an escape for her and the new - born child. It could add an element of intrigue and hope to the otherwise very bleak scenario of her giving birth in the tower.
Ron is often involved. He's Hermione's husband in many fanfictions, so he'd be there to support her during the birth. Harry might also be present, as he's their close friend. He could be the one to ensure their safety during this vulnerable time. Ginny could be another character, perhaps helping Hermione through the labor process, offering her the kind of female support that's important in such a situation.
Obi - Wan Kenobi would be one. He's Anakin's master, and in the fanfiction, he might suspect something about their relationship and have to decide whether to support them or uphold the Jedi Code.
One interesting aspect could be the exploration of Padme's emotions during the birth. In fanfiction, authors might delve deep into her fear, joy, and anticipation all at once. Maybe she has premonitions about the future of her child in some stories.
His friends like Hermione and Ron could also be important characters. Hermione might use her intelligence to help Harry during the pregnancy and after the birth, while Ron could provide some comical relief with his typical reactions.
Harry Potter himself is often a popular choice. Given his central role in the original series, fans like to explore different and unique scenarios with him, such as him being the one to experience mpreg. It adds a whole new layer of drama and intrigue to his character.
Alina is also frequently involved. Her connection to the Darkling in the original work makes her a natural addition in many fanfictions. Their complex relationship can be further explored or even rewritten in different ways in fanfiction.