Warning! Spoilers ahead for Batman/Fortnite: Zero Point #6
In the latest issue of DC's sent through a rift to Fortnite Island, becoming trapped in an endless time loop of battles and craziness. However, while the Dark Knight and Selina Kyle managed to break out of the loop and find a way off the island, Harley elected to stay, claiming that she feels right at home with all the wacky madness. However, this is a decision that the Joker probably wouldn't make despite his claims to be a lover and agent of chaos itself.
In prior issues of Batman/Fortnite: Zero Point from Donald Mustard, Christos Gage, Reilly Brown, Nelson DeCastro, John Kalisz, and Andworld Design, Batman and Catwoman had ed with a team of like-minded fighters who had also broken out of the time loop. Working together, they managed to locate the Zero Point, a gateway to worlds across the omniverse. While they were able to transport everyone back to their respective homeworlds, the Bat and Cat were betrayed by Deathstroke, revealed to be working with the organization controlling the island itself. Slade Wilson abandoned them to live out the rest of their days on the island, but there was still one person who could help them get back: Harley Quinn.
Upon her arrival to Fornite Island, Harley Quinn instantly adapted according to the Dark Knight, and it makes a lot of sense. For someone as unhinged as Harley, Fortnite is a utopia. While Batman and Catwoman were fighting to escape, Harley was just fighting, dancing, dying, and doing it all over again, totally thriving on the pure chaos. As a result, she refuses to go with the heroes when they need her to get back to Gotham City, choosing to stay in her new home instead.
While Batman ended up knocking Harley out long enough to access the Zero Point to get back to Gotham, she quickly left Batman and Catwoman as soon as she woke up, loving Fortnite Island too much. While it's a choice that very much fits her character, it doesn't seem as though it would vibe very well with the Joker despite his shared adoration for chaos. While Joker claims to be an agent of chaos he actually prefers to direct it, always having some sort of plan or agenda. In contrast, Fortnite and its battles don't really have any sort of end goal, and even victory is met with a simple reset where a new battle starts up again.
As a result, it seems as though Harley loves true chaos more than Joker does, especially if it's chaos he can't control or provoke in any way. In any case, it's going to be interesting to see what happens to Harley Quinn should a new DC crossover happen with Fortnite. Regardless, she certainly seems to be quite happy, finding her own personal paradise apart from Gotham City and the DC Universe.