A heroic type of character might see the Sans fight as a great challenge. They would be eager to face him and prove their worth. They might respect Sans as a worthy opponent and try to fight him honorably.
Rainbow Dash might see humans as potential rivals in terms of physical abilities. She'd be eager to show off her flying skills and might challenge a human athlete to a friendly competition. And if the human showed some really cool skills, she might gain respect for them. Pinkie Pie, of course, would just be all over the humans. She'd throw parties for them, introduce them to all her friends, and make sure they had a great time in Equestria. She doesn't really care about differences; she just wants to have fun with everyone.
If it's a romantic fanfiction about him and Annabeth, he might blush a bit. After all, it's about his relationship. But he'd also be happy that people see their love as something worth writing about. If it's an action - packed fanfiction that has him on a new adventure, he'd be excited. He loves adventures, and seeing new ideas for his heroic deeds would be appealing to him.
For the romantic fanfictions, Sirius would probably be all for it, especially if it involved some steamy relationships. He'd be like, 'Ooh, this is spicy!'. James might be a bit more reserved, especially if it involved his relationship with Lily in a way he didn't like. Remus would be interested in how the relationships were developed. In adventure - based fanfictions, Sirius and James would be excited, seeing new adventures in the wizarding world. Remus would focus on the logic and the world - building in those stories.
Well, if it's a comical Spider - Man fanfiction, Clint would be the first to laugh out loud. He has a good sense of humor and would enjoy the light - hearted take on Spider - Man. When it comes to dark and gritty fanfiction, Steve might be a bit concerned. He believes in the positive image of heroes, and such fanfiction could go against his ideals. Tony, however, might see it as an interesting exploration of the character's potential in different situations.
Frisk could be one of the characters watching. Given their role in the game, they would be interested in Sans' fight as it could impact their journey through the Underground. Additionally, Undyne might be present. She's a strong fighter herself and would probably be sizing up Sans' techniques, maybe even learning from him or being critical of his fighting style depending on her mood.
There are many possibilities. A character who is always looking for new knowledge or experiences might be very interested in the fanfic. They could study it to understand how fans view their world. On the other hand, a character who is more traditional might reject the fanfic completely, seeing it as a deviation from the 'true' story. And then there are characters who might be inspired by the fanfic to try new things in their own in - universe lives.
In many fanfictions, Natsu's relationships are explored differently. If it's a fanfic about Natsu and his relationship with the guild as a family, then characters like Mirajane would be very nurturing towards him. In a fanfic where Natsu is on a solo adventure, the guild members would be eager to hear his tales when he returns. They might be excited, like Kinana, or skeptical, like Gajeel, depending on the details of the fan - made story.
Protagonists drive the plot forward as the story mainly focuses on their journey. Antagonists create obstacles for the protagonists, which adds tension and conflict. Secondary characters can provide support or distractions for the main characters, influencing their decisions. Flat characters, while not as complex, can set the scene or give simple information that helps the plot progress.
Heroes drive the main plot forward. They are the ones who face the big challenges and strive to overcome them. Villains create the conflict that the heroes must deal with. Without villains, there would be no real story. Magical creatures add an element of wonder and mystery to the story.
In the fanfiction, a character might also react with confusion. Sans' attacks and his overall fighting style can be very unique and hard to understand. A character who is used to more straightforward combat might be completely bewildered by Sans' moves, not knowing how to counter or even react properly.