Jason Momoa will get some help defending Atlantis against interlopers from a teenage warrior—Deadline reports that Ludi Lin, who played the Black Ranger in the rebooted Power Rangers, has joined the cast of Aquaman. Lin is set to play Murk, the leader of the Men-of-War, which is like the Atlantean infantry. He’s also Aquaman’s “trusted ally,” and will help Arthur Curry battle his half-brother Orm Marius (a.k.a Ocean Master), who’s played by Patrick Wilson, as well as Yahya Abdul-Mateen II’s Black Manta.