Well, in many such fanfictions, Percy might be extremely flustered. He could blush furiously and quickly look away, being the gentleman that he is. After all, he has deep respect for Annabeth.
Percy might initially be shocked. His mind could go blank for a moment. But then, depending on the context of the fanfiction, he might also try to be cool about it and make a joke to ease the awkwardness, like 'Nice... uh, armor?'. This shows his ability to handle unexpected and embarrassing situations in a somewhat light - hearted way.
In some versions, Percy's reaction could be more complex. He might have a mix of emotions. On one hand, there's the natural physical attraction which causes his heart to race a bit. On the other hand, he's worried about how Annabeth will feel about him seeing her in such a state. So he might start stammering out an apology while still trying to keep his eyes averted, all the while his mind is racing with thoughts about their relationship and how this moment might change things between them.
Annabeth could also try to solve the problem that's making Percy cry. If it's related to a quest or a danger, she'll start thinking of ways to fix it. In some fanfictions, she might say 'Don't worry, we'll figure this out together.' and then start making a plan.
She might be initially stunned. After all, Percy is a hero and his well - defined muscles could be a sign of his strength and capabilities. It could make her blush a bit, secretly admiring his physical form while also feeling a bit flustered as she tries to maintain her usual composed self.
She might immediately go to comfort him. Annabeth is a strong and caring character. When she sees Percy cry, she could put aside whatever she was doing and just be there for him, offering a shoulder to lean on or some soothing words.
He could also become withdrawn and depressed. Percy and Annabeth have a very strong bond, and her death would leave a huge void in his life. He might isolate himself from his friends and family, lost in his grief and memories of her.
She would likely be furious at first. After all, it's a huge invasion of privacy.
In fanfiction, Annabeth's reaction could be very complex. She could immediately reach out to touch the scars gently, a sign of her closeness to Percy. She might ask him about each scar, wanting to know the story behind it. This would not only show her concern but also her curiosity about Percy's past. It could also lead to a moment of bonding between them, as Percy shares his experiences related to the scars and Annabeth listens intently, further strengthening their relationship.
Annabeth could also be angry, not at Percy but at the situation or the forces that led to his death. She might vow revenge and start on a journey to find out who or what was responsible for Percy's sacrifice and make them pay. This could lead her into a whole new set of adventures and challenges as she tries to come to terms with her loss.
She might be heartbroken at first. She could try to jog Percy's memory by showing him things that were important to them.
He could also become angry. Percy has a bit of a temper, and he might lash out at Annabeth, demanding an explanation. He might feel betrayed, especially if he doesn't understand the real reasons behind the break - up. In his anger, he could distance himself from their mutual friends and go on solo quests to clear his head.
One possibility is that it could lead to some awkwardness between them for a while. They might avoid each other's eyes and have stilted conversations until they finally talk about what happened and clear the air.