At first, Naruto would likely be very confused and hurt. He has always craved family love and acceptance, so this sudden turn would be a huge blow. He might try to plead with his family, asking them to believe him and give him a chance to explain.
His family would probably be overjoyed. After all, they might have thought they'd lost him forever. There would be hugs and tears, and a flood of questions about his life and what he's been through.
Shikamaru, being the laid - back yet perceptive friend, would probably think that Naruto has a plan. He would be concerned but also understand that Naruto is not one to make hasty decisions without a good reason. He might keep an eye on Naruto's family in his absence and hope that Naruto will return safely one day.
Well, Spy x Family fanfiction can be really interesting. Some fanfictions might explore different relationships between the characters in more depth. For example, they could focus on the bond between Anya and Loid in a new situation that wasn't shown in the original manga or anime. It's also fun to see how authors play with the spy and assassin themes in unique ways.
Harry could also be very hurt. He might start to question what he did wrong and try to talk to Ginny to find out the reason. He might say things like 'Ginny, I don't understand. What have I done?' in an attempt to clear up the situation.
Percy's reaction could be complex. Initially, he'd be hurt and angry. But as time passes, if Annabeth is sincere in her attempts to get him back, he might start to question his own feelings. He could be torn between his love for her and the pain of the betrayal.
In the long run, Percy might grow from the experience. He could become more cautious in his relationships and less trusting. Or, if there's a chance for redemption in the fanfic, he might be open to forgiving Annabeth if she shows true remorse and has a valid reason for her actions. But initially, it would be a very difficult and emotional time for him.
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.
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.
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.