The Joker could make a decent Robin if he just had a decent life somewhere in DC's Multiverse. Gotham’s notorious Clown Prince of Crime always butts heads with Batman in some capacity, but the two don’t exactly hate each other. What started as a simple rivalry turned into a sick and obsessive relationship where both sides became dependent on each other. That said, if The Joker didn’t lose his mind, his connection with Batman could be healthy, even making way for the Clown Prince of Crime to become the perfect sidekick for the Dark Knight.
Source：https://www.cbr.com/batman-joker-robin-dc/
