Because of his stitches on his mouth. and I think it’s probably true but it’s also the same face as death in problem sleuth!  I tend to believe that Kurloz might be some kind of stand-in for death. He’s also mute. 

I mention he is mute because there was a custom in European culture up to about 1914 where a mute would stand at the door of the church during a funeral. mutes were considered a symbolic protectors of the diseased! They were considered professional mourners and they would wear somber clothing, like dark clothes and cloaks as well. so i thought that was pretty interesting and that i would share. perhaps Kurloz isn't as evil as we think?