One Joker?
I think they said that there are actually THREE-Jokers in the regular Batman comic book series.
They have yet to reveal if they are related (brothers, siblings, etc).
Wish the Batman was on the Mobius Chair and got a shock when he asked about The Joker, that they would finally reveal what Batman was told.
(I don’t include the Batman-Who-Laughs as a true Joker, while some my disagree.)