Stitch (aka Experiment 626) is an upcoming third-party character that will appear in the ??? Series and his rival was Mad Max (Character).
Name: Mad Max
Connection: They are both powerful, their films are aimed at different age groups and different mediums (Mad Max originated from an R-rated live-action film franchise that is aimed at adults while Stitch originated from a PG to G-rated animated film franchise that is aimed at children), and etc.