She might be overjoyed. Abby has a deep connection with Clarke, and in fanfiction, her first reaction could be pure elation. She would probably rush to see Clarke immediately, tears of happiness in her eyes.
She could be ecstatic. After all, if they have a close relationship, the thought of Clarke being alive would be like a dream come true for Abby.
In the fanfiction, Abby finding out about Clarke being alive could be a turning point. If Abby was in a difficult situation before, this news could give her new hope. She might start making plans to reunite with Clarke. It could also affect the relationships between other characters. For example, if there were some who thought Clarke was dead and had moved on in some way, Abby's discovery could stir things up.
Abby might react quite strongly. Given her relationship with Clarke, she would likely be very interested in what is being written about her in the fanfiction. She may try to find the author to ask about their intentions. If the fanfiction has Clarke in some sort of dangerous or inappropriate situation, Abby would probably be quite worried and might even try to get it removed. However, if it's a positive and creative take on Clarke, she could see it as a compliment to her daughter - like figure and might encourage others to write more positive fanfiction about her.
She might be initially shocked. If the fanfiction contains some untrue or inappropriate things about Clarke, Abby could be protective and try to find a way to stop it from spreading.
Mal might be hesitant at first. She'll need time to process this new information. She may start to recall past interactions with Audrey in a new light, wondering if there were any signs all along. And she might worry about how this new relationship will be perceived by others in the fanfiction world.
She might be really angry. In the context of fanfiction, Betty could see this as a betrayal of their relationship in the story's universe. She might confront Jughead immediately and demand an explanation.
She might be initially shocked. In many fanfictions, Bella is shown as being stunned into silence for a moment, unable to process the news right away.
She might be extremely angry. In many fanfictions, Ginny is a strong - willed character. So, she could immediately seek justice for Harry, perhaps by confronting those who were responsible for the abuse in the story.
She could be initially shocked. After all, finding out your friend is a superhero is a big deal. But then she might become excited and want to be more involved in Peter's Spider - Man life.
One possible reaction could be excitement. If 1a is a fan of the character Endeavor, finding fanfiction about him might open up new storylines and perspectives that they hadn't considered before. They could be eager to dive in and explore these fictional tales.