The 2025 movie Superman: Legacy has cast three more surprising roles: Nathan Fillion as Guy Gardner Green Lantern, Isabela Merced as Hawkgirl, and Edi Gathegi as Michael Holt Mister Terrific (via Vanity Fair). Considering that Superman: Legacy will be about a young-ish Clark Kent settling down in Metropolis after leaving Smallville, the fact that all these other heroes will appear in the movie is a bit unexpected. But since this is also the movie that will launch a whole new DC universe under the purview of James Gunn and Peter Safran, it makes sense to establish early that Superman is only one part of a larger mythology.
Nathan Fillion is an internet favorite for myriad reasons, such as for his time playing Captain Malcolm “Mal” Reynolds on Firefly, and he has furthermore voiced renditions of Green Lantern in animation before. James Gunn also just enjoys casting people he already likes, and Fillion starred in Gunn’s Slither, in addition to having supporting roles in The Suicide Squad and Guardians of the Galaxy Vol. 3. It kind of just feels like fate that Nathan Fillion will play a Green Lantern in Superman: Legacy, though with Fillion currently being 52, it sounds like they’ll be aging Guy Gardner up relative to Superman. (It’s also worth noting that a Green Lantern TV show is still in development, which will focus on Hal Jordan and John Stewart.)
Meanwhile, Isabela Merced played the title character in Dora and the Lost City of Gold, which makes her the perfect Hawkgirl (I presume). And Edi Gathegi was Darwin in X-Men: First Class and whoever Laurent is in the Twilight movies, so he’s no stranger to superheroes and supernatural powers either.
Previously, David Corenswet and Rachel Brosnahan were cast in Superman: Legacy as Clark Kent and Lois Lane, respectively. The film will begin shooting in January 2024. Meanwhile, Blue Beetle is now officially being considered part of the new DC universe as well, though the story stands on its own. In fact, Gunn and Safran want all of their upcoming stories to stand on their own as natural starting points to the DC universe — even Peacemaker season 2, which is somehow also now part of this new universe.