Novelizer is an AI writing assistant application that helps users create novels. Users can set a novel title, main characters, and determine the development of each chapter. The application automatically generates continuations based on previous content, and users can also use the multiple-choice mode. The new version adds a multiverse feature, allowing users to change the direction of the novel's development as needed. The application uses OpenAI's language models to generate text, offering both GPT-3.5 and GPT-4 options. Users can edit and customize within the application and collaborate with friends to write novels.