The main characters are obviously Sam, Jessica and their baby. Sam and Jessica are the parents, and the baby is the new addition to their family that will likely drive the story forward.
It could also involve the baby having some special ability or characteristic that makes their family's story unique. For example, the baby might be a prodigy in some way, and Sam and Jessica have to navigate how to support and protect their special child.
Obviously, Dean and Sam are main characters. They are the protective older brothers. And then there's the baby sister, who is likely a central figure as well, with her own personality and role in the fanfiction. There might also be other recurring characters from the 'Supernatural' universe like Castiel who could play important parts in the story.
Obviously, Loki would be one of the main characters. And of course, his baby. There might also be other characters like Loki's friends or enemies from the original mythology or the related fictional works, such as Thor, Odin, or the Avengers if it's set in a more modern - day superhero - related universe.
Vlad could be a great antagonist. He might see the baby versions of Danny and Sam as an opportunity to finally get rid of Danny for good. He could try to use their weakened state to his advantage and steal Danny's powers once and for all.
Well, clearly Naruto and Jetstream Sam are the main characters. Naruto, a young ninja from the Hidden Leaf Village with his orange jumpsuit and dreams of becoming Hokage. Jetstream Sam, on the other hand, is a skilled swordsman with his own set of unique abilities.
Well, obviously Sam and Tim are the main characters. Sam might be the more impulsive one, always ready to jump into action, while Tim could be the more cautious and strategic thinker.
There could also be some human characters in the fanfiction who are friends with Bella. These characters might not understand her relationship with Sam at first and could cause some drama. They might try to pull Bella back into the normal human world, while she's being pulled towards Sam and the werewolf world.
Obviously, Jessica is a main character since she's in the title. There might also be characters who oppose her rule in the dark side. Maybe there are some sidekicks or allies that help her maintain her power.
Another theme is the idea of redemption. Some fanfictions have Jessica coming back in some way, and Sam sees it as a chance to make things right, to protect her better this time. It's like he gets a second chance at their relationship, which ties into the whole redemption concept in the Supernatural world.
The main characters are Harry, who is the focus as Sam and Dean's sister. Sam, who is good at research and understanding the deeper aspects of the supernatural. And Dean, who is more hands - on and ready to fight. Their different personalities and how they interact with Harry form the core of the story in this fanfiction.