The Batman courtesy Warner Bros Entertainment The Batman courtesy Warner Bros Entertainment

As the fourth season of The Batman (Saturdays at 10:30 am/ET, on the CW) winds down, the Caped Crusader is starting to make some superfriends. In the two-part season finale, which begins this Saturday and concludes on May 5, Batman joins forces with Martian Manhunter to stop an alien invasion in Gotham City. And that's just the beginning: When the show returns this fall for Season 5, a parade of superheroes will guest-star. "Martian Manhunter is starting the Justice League," executive producer Alan Burnett says, "and he would like nothing better than to have Batman on the team." Also on the guest list: the Flash, Green Lantern, Green Arrow, Hawkman and Superman. And though the Dark Knight Detective and the Man of Steel are the ultimate good guys, don't expect them to be instant friends. "Their first meeting is a little contentious," Burnett teases. "These are two guys sizing each other up." We can hear it now: "My cape is bigger than your cape." - Reporting by Rich Sands