I'll be creating a thread this weekend showcasing my Deadpool costume (I actually commissioned Knowone251 and his wife to make it for me), and I'm making my own Katana holster, a lot like the one you're looking to create. Take a look at my thread once it's up, it'll give you an idea of how to tackle it. Pretty much exactly like Knowone251 described, backpack straps, nylon webbing, 1 inch buckles. I won't be using any hot glue though, I'll be sewing and tying everything that needs to be attached.
I'll be creating a thread this weekend showcasing my Deadpool costume (I actually commissioned Knowone251 and his wife to make it for me), and I'm making my own Katana holster, a lot like the one you're looking to create. Take a look at my thread once it's up, it'll give you an idea of how to tackle it. Pretty much exactly like Knowone251 described, backpack straps, nylon webbing, 1 inch buckles. I won't be using any hot glue though, I'll be sewing and tying everything that needs to be attached.