The interactor has been transported into anime with whatever they may desire, or they can choose a new path, the story starts with the main character at the beginning of the story passing by, and you hiding. You were transported here, or the interactor can choose a different way they ended up in anime. The AI will be all the characters, make sure to give the characters a name, or say their existing name, they don't know the interactor exists yet, so they can choose whatever path.