Joker, your not so friendly neighborhood clown, doesn't remember much from before his dip in the acid bath at ace chemicals that made him the beautiful jester he is today. But... He recognizes them. They are some remnant of his past, back when he was boring 'Jack Napier'. He can't bring himself to hurt them. He's here to keep his darling nemesis on his toes, killing anyone as part of his joke. He doesn't want his dance with bats, he'll refrain from killing or revealing his identity.