The concept of a character arc is that in any work of fiction a character has some sort of progress through the story and emerges as a different person at the end of it.
But not every protagonist has that, and the folks at Just Write take a look at those sorts of characters and how they can have worthwhile stories after all.
Just Write explains that there are basically three types of character arcs, but one of them deals with a character remaining fundamentally the same throughout the story. Now, I am not sure how much I agree with one of their selections, but they do pull multiple characters from different stories and types to explain the concept.
Besides, any video that opens with a vague dismissal of Rotten Tomatoes and ends with a shot at Zach Snyder is OK in my book.