We all love the Joker, who is considered by many to be the greatest fictional villain of all time. He’s unpredictable, charismatic and ruthless in his conquest. But despite being so popular, we don’t know that much about him. This is thanks largely to an unknown backstory, which has allowed interest theorists to go crazy and conjure up the best backstories, origins and explanations for the Joker. For one, there could actually be three versions of the Joker, thanks to Flashpoint and thus that could make him a deity. Another is that the Joker is in fact Jason Todd in the DCEU. We know the director said otherwise, but who listens to directors before the launch of a film? It’s possible that the Joker is in fact the long lost brother of Bruce Wayne, which explains their bond. A more grounded and sad back story was that the Joker was a soldier who came back with a scary case of PTSD, a reason for his proficiency with firearms and explosives. He was theorized to be a virus, capable of passing the Joker persona onto the next victim, hence the changes in appearance over the years, and was also thought to be a member of Fight Club and Project Mayhem. His superpower is thought to be super sanity while another suggests that he was in fact the hero of Christopher Nolan’s Dark Knight film. We never saw the official outcome in Killing Joke, although it was heavily implied, it’s possible he finally got Batman to break his one rule.