GasparZizou
Super Freak
I had a thought on who Arkham Knight might be today. Since we're still unclear on the timeline so far, it is possible Arkham Knight could be Harley Quinn's son? We know there was the possibly fake pregnancy test in AC, but I don't think enough time has passed from AC to AK for that to be the case (maybe I'm wrong). But another possibility is the child being Deadshot's and not the Joker. If you've watched Assault on Arkham, you'll understand that theory.
I realize AK being Harely's son is pretty unlikely given that a good 18-20ish years would need to pass for it to be even remotely possible. But it would at least be a logical new character that has been created though events on the story rather than just a new character out of the blue.
Also, if I'm not mistaken RS stated that Harley wasn't pregnant after all, it was supposedly a psychological pregnancy due to how much she wanted to have Joker's babies
They said it was just an idea they were toying around with.
But who knows... But yeah considering how nobody looks like more than 10 years older, it's unlikely.