Aldo (アルド Arudo) is a private devil hunter from the United States. Unlike his brothers, Aldo is actually a very sensitive person. He's easily scared by the deaths of other people, his common reaction being to puke when he sees a corpse. He also empathizes with the person he is acting as, to the point of crying once he learns about his life. He tends to be very insecure and constantly reassures himself that he's immortal and that he can do the thing he sets his mind to.