Thanks for playing my game bro, so a lot of questions but I will try to answer all.
1. I want to add fighting mini game, but I need to ask to my friend some help (he also make ren'py games his name is Dageta on itch.io btw)
2. Maybe I add the breathing styles, I actually don't know how to implement this but I will try
3. Female Muzan, I want to add too, but first Daki.
4. About the male demon slayers, I just never added it and I don't know why actually, but I can try to add it for sure.