Percy would likely be both angry and calculating. He'd be angry because he's been kidnapped, but he'd also start thinking about how he can use his powers and skills to get out of the situation. He might try to reason with Khione if he thinks it could buy him some time to plan an escape. He'd also be looking for any weaknesses in Khione's defenses or in her personality that he could exploit.
Well, initially Percy would be shocked that Khione has managed to kidnap him. But then his survival instincts would kick in. He'd probably assess his surroundings quickly, looking for any means of escape. He'd also be thinking about his friends and how they might come to his rescue. Percy would likely keep his cool as much as possible, trying to figure out Khione's motives. He might try to engage her in conversation to see if he can learn more about why she's done this. And he'd be constantly on the lookout for any opportunity to break free and fight back against her.
Percy would probably be angry at first. He has a strong sense of justice and being kidnapped against his will would make him fight back. He might immediately try to use his water powers to break free or at least create a distraction.
He could also be initially confused. Sasuke has known Sakura for a long time, and this unexpected act from her would leave him wondering about her motives. He may hold back his anger for a while to hear her out and understand why she did such a thing.
Naruto would probably be really angry at first. He's a free - spirited person who doesn't like being forced into things. So he'd likely try to fight back right away, yelling at Sasuke about what he's doing.
Well, perhaps a plot twist could be that Percy's friends think he's been kidnapped by someone else entirely. So they're looking in all the wrong places while Khione has him hidden away. Or, it could be that Khione kidnaps Percy but then realizes she's made a huge mistake because Percy has some sort of connection to a force that can destroy her. So she has to figure out a way to either let him go or use him to her advantage in a different way. Also, what if Percy is able to communicate with the elements in Khione's domain and he uses that to his advantage to escape or gain the upper hand?
Annabeth would be furious. She'd immediately start planning a rescue mission. She might call on all of Percy's friends and allies at Camp Half - Blood. Annabeth would use her strategic mind to figure out where Nico has taken Percy and how to get him back.
At first, Percy would likely be angry. He has faced so many challenges with the belief that his father was on his side. The betrayal would make him feel like all his efforts were in vain. He could lash out, perhaps even using his powers in a more reckless way. But as time goes on, he might start to question if there's a deeper reason behind Poseidon's actions and try to find out the truth, especially if he still has friends who believe in him and encourage him to look deeper.
At first, Sans would probably be a bit shocked, but then he'd turn on his laid - back, sarcastic attitude. He might make jokes at Gaster's expense, which could either annoy Gaster or make him respect Sans more. If Gaster tries to harm him, Sans could use his shortcuts to dodge attacks and try to find a way to reverse the situation. He'd also likely be thinking about how this affects his friends in the Underground, especially Papyrus, and try to find a way back to them.
He'd probably be devastated. Percy loves Annabeth deeply, so this would be like a punch in the gut for him.
Annabeth would probably be a mix of amused and exasperated. She might tease him a bit at first but then help him out if he's in an uncomfortable situation because of the dress. Grover would be really shocked at first but then try to be supportive. He might say something like 'Well, Percy, you look... different, but it's okay!'. As for Tyson, he would just be happy to see Percy and not really care about the dress all that much.
He could also be very kind and gentle in his reaction. Percy might not want to hurt his friends' feelings, so he'd try to let them down easy if he doesn't feel the same way. He might say something like 'You're a great friend, and I value our friendship so much' to show that he cares about them but not in that romantic way. On the other hand, if he has some hidden feelings for one of them, he could start to show more interest in return, like spending more time alone with that friend.