10 Worst Things DC Has Ever Done To Harley Quinn
3. Having Her Replaced
The discovery that there are, in fact, two Harley Quinns in Batman: White Knight is perhaps the biggest surprise in the entire series - which, given the wild ride a non-villainous Joker is, says a lot. The cliff notes are that one of the pair is with the reformed Joker, who is going by the title of Jack Napier, and the other was with the Joker while he was in full villain mode, and wants him to convert him back to his old ways.
There are positives to this scenario - for example, Harley's disses directed towards her 'new' self are clearly jabs at the new costume and character developments that the character has had in recent past, which you're sure to get a kick out of if you've kept up to date with the character.
But it also adds some fairly needless complication to the plot, while also implying that Harley is a replaceable character - which seems pretty harsh, all in all.
It's certainly an interesting choice to have two Harleys - but also one that wasn't totally necessary for the plot of the overall comic.