Wikipedia:When and how to create a sub-page of a fiction article

This is an essay.

It contains the advice or opinions of one or more Wikipedia contributors. This page is not an encyclopedia article, nor is it one of Wikipedia's policies or guidelines, as it has not been thoroughly vetted by the community. Some essays represent widespread norms; others only represent minority viewpoints.

This page in a nutshell:

Articles on elements of fiction should follow the principles of Summary style.
An article that meets the general notability guideline is presumed to satisfy the inclusion criteria for a stand-alone article

An element of fiction is (1) an individual component of a serialized work, such as a television episode or a comic book storyline, or (2) an element in the fictionalized world, such as a character or setting.

Wikipedia articles tend to grow in a way which lead to the natural creation of new articles. The text of any article consists of a sequence of related but distinct subtopics. When there is enough text in a given subtopic to merit its own article, that text can be summarized from the present article and a link provided to the more detailed article.

When an article on a fiction topic has a section that has developed to the point where it can be considered to be broken out in Summary style then consideration needs to be given to ensure the new article will meet the general notability guideline.