Bella herself can also be part of these fanfictions in terms of how she reacts to the muscle growth of the male characters. Her perspective, whether it's admiration, fear, or something else, can add depth to the story. Also, sometimes in unique fanfictions, she might even have some form of power - related muscle growth herself.
Obviously Naruto himself is often the main character as it's about his muscle growth. Sasuke can also be involved, perhaps as a rival who is both impressed and a bit envious of Naruto's new - found physical power.
Bella and Edward are often main characters in such fanfiction. Since their relationship is central in the original Twilight series, in fanfiction about sacrifices, they could be the ones making sacrifices for each other. For example, Edward might sacrifice his vampiric nature to give Bella a more 'normal' life if she so desires.
The Volturi leaders also frequently show up in these fanfictions. Aro, Caius, and Marcus. Their actions and decisions can be completely different in an alternate ending. They could be more benevolent or perhaps more devious. Their relationship with the Cullen family and Bella can take on new twists and turns.
The Cullen family members are often main characters. Edward, with his brooding nature and ability to read minds, is likely to be involved. Bella might also be there as she is closely tied to the family. And Carlisle, being the patriarch, often plays a crucial role.
Ben Tennyson is almost always the main character in 'ben 10 muscle growth fanfic' since it's based on the Ben 10 series. His transformation and the resulting muscle growth are central to the story. Sometimes, his alien forms might also be involved in a different way because of the muscle growth concept.
Obviously, Naruto is often the main character in 'Naruto hyper muscle fanfic' as the concept revolves around him having hyper muscles. His friends like Sasuke and Sakura are also likely to be involved. Sasuke might be initially jealous of Naruto's new power or might be inspired to train harder. Sakura could be the one to help Naruto understand and control his new strength from a medical ninja's perspective.
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.
Charizard is quite popular in Pokemon muscle growth fanfiction. Its large size and natural strength make it a prime candidate for stories about muscle growth. Machamp is another one. With its already muscular physique, fanfiction often explores how it can further enhance its muscle power. And then there's Gyarados. The big, powerful water - type Pokemon can be depicted in fanfictions as growing even more massive muscles, perhaps due to some special underwater training.
Twilight's friends like Pinkie Pie, Rainbow Dash, Rarity, Fluttershy, and Applejack can also be part of these fanfictions. They might be shown in flashbacks or回忆 related to Twilight's past, perhaps showing how they first met or how Twilight's view of them changed as she got to know them better over time.
Well, the main characters are usually the wolf pack members. In the Twilight context, that could include Sam Uley, who is often a leader - type figure in the pack. Jacob is also very likely to be involved as he has a major presence in the Twilight wolf pack storylines. As for the shared mate, it could be a human character, perhaps someone with a connection to the supernatural world in the Twilight universe. This character would be at the center of the complex relationships and story arcs involving the wolf pack's shared claim on them.