Grover could be a great addition. He could be the goofy but loyal friend who always gets caught in the middle of Percy and Annabeth's drama. For example, he might accidentally spill some secrets that cause more trouble between them. Another good character could be Clarisse. She could be the school bully who has a grudging respect for Percy and Annabeth but still tries to cause problems for them now and then.
In some fanfictions, there could be a plot where Annabeth is jealous of a new girl who seems to be getting too close to Percy at school. Percy, on the other hand, is oblivious to the girl's intentions. Annabeth has to deal with her own insecurities and at the same time figure out how to make Percy realize what's going on without sounding too possessive. This kind of love triangle - ish situation can add a lot of drama to the story.
One idea could be that Percy and Annabeth are new students at a high school filled with mythological secrets. They have to hide their demigod status while also dealing with normal high school problems like exams and bullies. Maybe they join the school's swim team and debate club respectively, which could lead to some interesting interactions.
One idea could be that they compete in various school competitions like academic decathlon or sports events, always trying to outdo each other. For example, in a science fair, Percy might do a project on underwater ecosystems because of his love for the water, while Annabeth does something related to architecture. Their rivalry makes them both push harder and come up with more creative ideas.
They could be involved in a high school project that turns out to be related to an ancient prophecy. Percy might use his water - controlling abilities in a science experiment in a really cool and unexpected way, and Annabeth would be there to explain the historical context behind it all.
There's Tyson, Percy's cyclops half - brother. In high school fanfiction, he can be really endearing as the big, strong but gentle guy. He might be on the school football team or something similar. And then there's Rachel Elizabeth Dare. She could be the artsy girl in school who has a bit of a crush on Percy and causes some jealousy with Annabeth, adding some romantic tension to the story.
Perhaps in this high school fanfiction setting, Percy has a different group of friends who don't like Annabeth. Their influence on Percy gradually makes him develop a dislike for her. You know, peer pressure can sometimes change a person's attitude towards others.
Percy could show up at Annabeth's high school during a big event like a pep rally. He sneaks in, disguised as a delivery person. When he finally reveals himself to Annabeth in the middle of the crowd, she's shocked but overjoyed. They hug and Percy tells her he couldn't stay away any longer.
Often in these fanfictions, the pregnancy is used to add drama. It might lead to conflicts between Percy and Annabeth, like differences in their opinions on how to handle the situation. For example, Percy might be more laid - back while Annabeth wants a more structured plan. It also might show their friends rallying around them or being shocked. And sometimes, it's a chance to see how they adapt to changes in their social status at school due to the pregnancy.
Often, it could be a jealous classmate. Maybe someone who has a crush on Percy and sees Annabeth as a threat, so they try to create problems between them. Another could be a strict teacher who doesn't like Percy's carefree attitude and Annabeth's independent thinking, always trying to give them a hard time.