How to write a story with hundreds of thousands of characters but save room for readers to imagine themselves into the story?

I have a lot of characters I have created, but I can't write all of them, I have their traits, physiques, backgrounds, relationships, personalities and everything. I want to release this story to the public, so I need to make room for readers' own versions of themselves, but I can't figure out how to do it without cutting and changing content. Does anyone have any suggestions for this?<br><br>I'm writing a fantasy story with a lot of fluffy content.