This is pretty old concept art, though I don't think a lot of us payed much attension to it. This is certainly something I've never really noticed before. But if you loook at the below concept art for
Beware The Batman, two characters (or two different concepts of the
same character) appear that bare a striking resemblance to the Clown Prince of Crime. Shout-out to "The Magnolia Killer" on
Beware The Batman Wiki for pointing this out.
In this first concept art page, look to the left and you'll see someone who kind of resembles The Joker:
The second page of concept shows someone who bares an unmistakable appearance assosiated with the infamous rogue. Look to the top left hand corner:
Considering more reconizable villains like Two-Face and Deathstroke are going to be introduced withing the second half of the first season, it's plausable that the Joker may have been considered for season two (assuming they planned that far ahead, even before it was clear that the show's renewal is highly unlikely). What do you think of this art? Do you think this is The Joker? Some kind of coincidance? Let me know what you think down below!