The brothers should've been identical twins

They make a big deal of hiding the front man's/brother's face. When the front man takes off his mask in the first ep, the camera only shows the back of his head. When the detective find the paper records, the shadows purposely hide his brother's picture. In the end, when the front man finally reveals his face, it's just some random guy we haven't seen before. Why was the point of hiding his face throughout the show if we don't even know him. It would make sense if they were identical twins.