Ok So I don't have fighting styles currently but It will be like this:
If you don't have a breath, you can get it. If you do, each trainer for it will say: ...
Your skills will require stamina to use.
There are two types of fighting styles:
Weaponless: You will use your fist or legs. (I'll post Ideas for these)And you will lose your rusty katana when you get the fighting style.
Weapon: You get these from the trainer when you learn it. (the later Idea for the fighting styles that use a katana or multiple katanas, the katanas will look like rusty katanas and when you craft your slayer nichirin, your sword(s) will look like it.)