Acharacter does not change during the course of the action.

A static character does not change during the course of the action.

Explanation:

This character does not undergo essential change in the development of the story.

remember, the goal of an adjective clause is to add more information to a noun or a pronoun. as you can see from the examples above, you can add information by including a longer adjective clause or tighten up a sentence by turning the adjective clause into an adjective phrase.