That's me. Its actually simpler than you think to make his standard outfit. If you are a male, make the collar and sew it to a muscle shirt. If you want to keep the collar up just use a small sturdy metal wiring like you find in bras and sew it into the inside of the collar. As for the pants, I just used a cotton fabric from each color and went (top to bottom) Grey for the belt, white for the main pants, black for the lower legs and gray for the bottoms. The belt is just a part of the pants and has two hole in the front where a string or rope can be tied for a belt and tucked in. The shorts go to his calves so they would need to be rather big to get the right look and try and make them flare out a bit. It just looks bad when you see a Black Star with tight fight shorts :<
Yes the Spartoi uniform is easier but most people don't immediately recognize it because they have only seen the anime and it does have a longer basic scarf.
Black Star is the most OP character in the series @.@