The Joker is likewise the longtime archenemy of Batman, whom he considers to be his have preferred "joke" and the murderer from the latter's protege, Robin, together with Harley Quinn. It can be from this Bruce deduces that the Joker won't treatment who Batman is; he only cares for Batman, http://laneehhdt.blogproducer.com/14990437/not-known-factual-statements-about-joker