Jack and Jill are the main antagonists of Puss in Boots.
Mean, greedy, and ugly, Jack and Jill are two nasty outlaws united in a life of crime. They are both brutish and violent. However, Jack seems to have a more sensitive side: Throughout the film, he suggests to Jill that they settle down and raise a child together, such as his favorite piglet Hamhock. Jill, however, is completely against the idea, preferring the criminal life instead.
In the film, Jill appears, along with two other females, appearing in the barn when Shrek and Donkey wake up and she fetches Shrek a pail of water. However, this is most likely a different Jill, considering her age.
In the film, Jack and Jill are first seen rolling into the town where Puss is staying, with three magic beans locked in a box in Jack's hand. The beans are stolen from them by Puss, Kitty Softpaws, and Humpty Dumpty.
It is later revealed that Jack and Jill were in cahoots with Humpty all along, as part of an elaborate ruse. When the Great Terror comes looking for it's child, Jack and Jill attempt to take the child for their own, but are stepped on by the Great Terror. During the credits, the two are seen in full body casts.