When Ruby Rose debuted as Kate Kane in last year’s “Elseworlds” crossover, not a minute was wasted in digging deep into the Bat-mythos for the first time in the Arrowverse. Gotham City was visited, with Arkham Asylum being a major location. Naturally, this led to a lot of easter eggs and references to classic Batman villains like Bane, Mr. Freeze, Riddler and more. The Batwoman pilot, which aired this past Sunday, went one further though and explicitly confirmed the existence of the Joker in the Arrowverse’s Earth-1.
Kate’s tragic backstory involves the (apparent) death of her mother and sister in a car accident, which Joker is kind of directly responsible for. The Clown Prince of Crime gave the Dark Knight the typical supervillain choice of coming after him or saving the Kane family. Batman thought he’d managed to do both by using his grappling hook to keep the Kane’s car on the bridge before heading off to catch the criminal. However, some shoddy engineering meant the car ended up sinking into the river anyway.
Of course, the Joker’s unmistakable laugh was heard in “Elseworlds,” when the Arkham inmates broke out, but this makes clear that he’s been the established scourge of Gotham for years. In fact, it also tells us that both Batman and his nemesis have been around since Kate was a child, so for at least more than ten years. Despite their fame in their hometown, however, it seems the vigilante and the villain were considered urban legends for all this time by the rest of the country (see: Oliver Queen’s comment in “Elseworlds”).
By the time of Batwoman, of course, Batman has mysteriously vanished three years prior, leading Bruce Wayne’s cousin to take over his mantle as the city’s protector. With Kevin Conroy playing an older Dark Knight in “Crisis on Infinite Earths,” though, we’re left to wonder if the hero and the Joker could appear on screen in Batwoman later down the line.