More story work going on here.
I have discovered a character that I complete forgot about, because their big scene didn't happen until now. I could go back through and write them in where they need to go, but I'm still working under the advice of so many writers to resist the urge to edit and revise until after I have the whole story written. I jump back all the time and add little notes for new scenes and changes to scenes in *chapter* 1,2 and 3, but so far I haven't significantly revised them. It makes sense now why that is the common wisdom among people who write longer fiction. The problem is, your brain just can't hold all the ideas that make up a good story at one time. I forgot a whole character. One that I have notes for and the bones of an arc for. As I was writing each scene, that character just didn't fire anything in my memory. I like to plan a bit and 'pants' a bit when writing because I like to know where the story is going, but i also like being surprised when characters do or say something I wasn't expecting. That also means that you run the risk of not remembering to write in a whole character. Nothing like learning by doing I guess.