One common scenario could be Percy revealing his true identity to save his friends. For example, in some fanfictions, his friends might be in danger because of a misunderstanding about him. So, he reveals himself as a powerful or special being to clear the air and protect them.
In some fanfictions, when Woody reveals himself to Andy, it could be a very emotional reunion. Maybe Woody has been lost or on an adventure far away, and his return brings back all the great memories they had together. Andy might be overjoyed to see his old friend again and they could start a new adventure right in their own backyard.
In fanfiction, when Harry Potter reveals himself, it could be a moment of great drama. Maybe he reveals his true identity to save his friends from a dangerous enemy. For example, if they are being tricked by a Death Eater in disguise, Harry might step forward and expose himself to stop the harm.
The Joker might be furious. His identity has been his biggest secret and Batman taking that away is like stripping him of his power. He could go on a wild rampage, more so than usual, targeting Batman directly and also anyone who he thinks might have had a part in the revelation.
Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.