There's also the possibility of a mixed reaction. She could be happy that Clarke is alive but also worried about what Clarke has been through. And she might be angry if there was some reason Clarke didn't contact her earlier, even if it was out of Clarke's control in the story.
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.
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.
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.
It could make her more determined. Abby might have been in a slump or feeling lost before finding out Clarke was alive. Now, with Clarke back, she could become more focused on their shared goals, like saving their people or fighting against a common enemy.
In this fanfiction, Abby and Clarke are likely characters within a particular fictional universe. They could be friends, colleagues, or even have a more complex relationship like a mentor - mentee relationship.
She could be confused at first. Fanfiction can be quite different from the actual story, and Abby might need some time to understand the concept if she's not familiar with it.
If Abby is open - minded about the fanfiction, it might not have much impact. But if she's not, she could start to view Clarke in a different light. For instance, if the fanfiction has some wild and uncharacteristic ideas about Clarke, Abby might subconsciously start to question Clarke's real motives or actions in a way she didn't before. This could gradually erode their relationship as Abby becomes more distant or critical.
I'm not sure specifically who Abby Clarke is in non - adult fanfic without more context. It could be a character created by a particular fanfic writer, or perhaps a name used in a specific fandom's fan - created stories. Maybe it's a new or relatively unknown character in a niche area of fanfic writing.
She might be overjoyed. After all, Naruto is her son. She could immediately rush to find him and embrace him tightly, tears of happiness streaming down her face.