In other cases, Teela's reaction could be a mix of emotions. She could be happy that Adam is such a powerful hero but also a bit sad that he felt the need to keep it a secret from her. This discovery might make her question their entire relationship up to that point, and she may need time to sort out her feelings about it all.
In certain fanfiction scenarios, Teela's discovery could lead to a whole new adventure. She might decide to help Adam keep his identity a secret more effectively. Or perhaps she wants to train with him, knowing he has the power of He - Man. Their relationship could shift from a simple friendship or comradeship to something more complex, with her having newfound respect for him and a deeper understanding of his responsibilities.
She might be shocked and feel a great deal of sympathy for Percy. She could immediately try to comfort him and assure him that he's safe now.
He would be very angry. Naruto is not one to take betrayal lightly.
He might be shocked. Fanfiction can often be quite different from the original source material, and the nogitsune concept is already pretty out - there. So the shock value could be high.
In some fanfictions, Vegeta is initially shocked. He might stand there in silence for a moment, his eyes wide. Then he could feel a strange mix of emotions, like pride and fear. He's proud to be having a child with Bulma but also fears for the safety of his family given his dangerous past and the many enemies he has.
In some fanfictions, Mary Jane's reaction can be quite complex. She could be a bit angry at first for being kept in the dark. However, her love for Peter would likely override that anger. She might start to worry more about his safety as Spider - Man, constantly fretting when he goes out to fight crime. She could also become more involved in his superhero life, helping him keep his secret and offering support in ways she didn't before.
She might be shocked at first. After all, it's not every day you find out your friend is a superhero. But then she could also be really excited and proud of him.
Ginny's reaction could also involve a sense of helplessness at first. But then she'd quickly gather herself and use her resources. For instance, she might call on her friends and family for help. She'd be by Harry's side constantly, using her presence to comfort him and also using her knowledge of magic to try and ease his pain.
She might be overjoyed. After all, Naruto is her son. She could immediately rush to find him and embrace him tightly, tears of happiness streaming down her face.
She's usually shocked and conflicted. It's a huge moment for her character.