Counting only characters who scheduled to appear in more than one chapter, Grassblades currently has a cast of 12. It's going to end up having somewhere in the region of perhaps 20 important characters by the end, unless I'm forgetting someone?
Of those, I'd consider maybe 7 to be the central cast (they'll be getting the most page-time), and maybe 4 of them are main main characters.
It might grow beyond that, but at this point ~20 is what I've got in my outline. I'm trying to focus on as few characters as possible for a story of the scope I'm attempting, because I want to give myself the time and space to really get into those characters and explore backstories and develop them properly.
... I tend to stick to rather small casts, whenever I can.