Perhaps in a different dimension or realm they visit in the fanfiction, the physical laws are such that Percy is smaller compared to Annabeth. In this new world, he would face challenges like not being able to reach things or being seen as less powerful just because of his size. But his relationship with Annabeth could grow deeper as she helps him adapt and he proves his worth in other ways.
One scenario could be that Percy has some sort of magic spell cast on him that makes him smaller. Maybe a mischievous god or a powerful enemy uses a spell to shrink him for their own amusement or to gain an advantage in a battle. This would lead to some interesting situations where Annabeth has to protect him in a different way than usual.
It could be a symbol of vulnerability. Percy is often seen as the hero, but being smaller makes him seem more fragile. This can add depth to his character as he has to overcome not only the usual challenges but also the limitations of his new size. It also gives Annabeth a chance to be more of a protector, which is a role reversal that can be interesting to explore.
One scenario could be that Annabeth accidentally revealed Percy's secret identity to someone he didn't want to know. This could put him in danger and make him furious with her.
One possible scenario is that Annabeth might lie to Percy about something really important. For instance, she could lie about her whereabouts when she's actually meeting someone who is not a friend to Percy. When Percy discovers the truth, he would feel betrayed and hurt.
One scenario could be that they are facing a powerful monster. The monster is about to strike Annabeth, and Percy jumps in front of her at the last moment, taking the fatal blow. Another possibility is that they are in a dangerous situation like a collapsing building or a sinking ship, and Percy uses his powers to ensure Annabeth's escape while he stays behind and perishes.
One scenario could be on a beach at sunset. The warm orange light is reflecting on the water, and Percy and Annabeth are walking along the shore. They stop, look into each other's eyes, and share a gentle kiss. It's a moment of pure connection and love.
One possible scenario is when Annabeth goes off on her own to solve a mystery or complete a task. Percy would worry about her getting into trouble without his backup. Another is when there are new and powerful monsters around that specifically target Annabeth because of her reputation. He would be worried about her facing them alone.
Perhaps in a scenario where Percy is about to sacrifice himself for the greater good. Triton, seeing Percy's selfless act, is so moved that he cries. Another situation could be when Percy is being wrongly accused and is facing great danger, and Triton, who knows Percy's true nature, cries out of frustration and worry for him.
Perhaps in the fanfiction, there are other characters who are jealous of Annabeth's intelligence or skills. So they start spreading rumors or making unfair remarks. Percy defends her because he knows her true worth and capabilities. He would stand up and say things like 'You don't know her like I do. She's always been there for all of us.'
One possible scenario could be that Percy sacrifices himself to save Annabeth from a powerful and deadly monster. Maybe a huge and ancient sea creature that only Percy can hold off long enough for Annabeth to escape, but at the cost of his own life.
Well, that could lead to a major shift in the story. Percy might be heartbroken and struggle to cope without her.