Batman and his arch-nemesis, Joker, have been locked in a war of good vs evil, order vs chaos, for the better part of eighty years. With their first encounter occurring in the pages of Batman #1, the Clown Prince of Crime has been established as a force for pure evil, even going so far as to murder a Robin. Throughout this time, one pressing question has been on the minds of fans: why doesn't Batman just kill Joker?
Source：https://www.cbr.com/why-batman-wont-kill-the-joker/
