Most stories have cast of characters fairly balanced between main players and side characters. The protagonists carry the story, and side characters will help the narrative along. Some have a Minimalist Cast, where the only characters that exist are main characters with major focus.
And then there's this trope: a cast of so many characters only Superfan is likely to remember them all. Even the creators themselves might not be able to remember them all.
Having Loads and Loads of Characters can be done for as many reasons as their are characters. The story might feature an Ensemble Cast. The extra characters might not have much more than a name and a title without their own plot or character arc, filling out the background to make the setting feel more lived-in and the main characters more connected to it. Or the characers might be a product of having so many plot threads to follow that each needs their own team to accomplish. Sometimes it's just a case of too many Ascended Extras.
Or maybe it's just a Long Runner. Soap Operas especially tend to have enormous casts as the series continues on for decades and actors cycle in and out of the show, creating the need for new characters to fill out the roster and introduce new plotlines to keep the story feeling fresh.
Regardless of the reason, this trope will need a lot of Cast Calculus to see how each of the characters and groups interact to handle well, and fan wikis are likely to be needed to keep track of everyone.
