Haha hi again!
Honestly I think any black headband will do!
Although I think it is supposed to be like the headbands from Naruto. You know, the ones with a metal protector on em
I also think that wig will work, looks like it's better quality than the one I wore on this picture.
The funniest thing about this is that I'm not even wearing a backpack. Those are a pair of white pants and the headband a pair of black tights.
I wasn't planning on making an actual cosplay, just something for fun out of the things I could find at home!
Hope this helped in some way