King Shark is one of the standout members of Task Force X in The Suicide Squad and he's played by both Steve Agee and Sylvester Stallone. One of the personal mandates James Gunn gave himself when he took the job of writing and directing The Suicide Squad was to choose the weirdest characters from DC Comics' pantheon in order to tell the sequel's story. That included people such as Javelin, Polka-Dot Man, and even King Shark.
Nanaue aka King Shark is Hawaiian and the son of the Shark God, and naturally, he's often appeared as a villain in Aquaman's comics, though eventually, he made his way into various runs of Suicide Squad. King Shark has recently appeared in The Flash TV show as well as the Harley Quinn animated series, but The Suicide Squad marks the first time that he's been adapted onto the big screen. And unlike his counterparts on-screen and on the page, the DCEU's version of King Shark isn't as muscular - instead having a form of dad bod.
To bring King Shark to life in The Suicide Squad, DC Films recruited Steve Agee to portray the character in person while on set, with Sylvester Stallone providing the voice of Nanaue. Agee is known for starring in the Gunn-produced film Brightburn as well as TV shows New Girl and American Princess. Meanwhile, Stallone is a world-renown actor, writer, and director, who famously made him for himself by creating the Rocky franchise, and then later starring in Rambo, Cobra, Demolition Man, and more. Recently, he created The Expendables and Escape Plan series.
Gunn said in a post-screening Q&A attended by Screen Rant that he and DC Films spent a great deal of time finding the perfect voice for King Shark, testing several voice actors and even one on-screen actor, but ultimately, Gunn reached out to Sylvester Stallone for the role, who graciously agreed to do it. Given the fact that the role was written with Stallone in mind, it only felt natural for those involved that he voice King Shark in the film. Stallone previously worked with Gunn on Guardians of the Galaxy Vol. 2 as well, portraying the character Stakar Orgord aka Starhawk, so they already had an established professional relationship.
King Shark became a beloved character ahead of The Suicide Squad's release and it's certainly possible that this is only the beginning of his DCEU tenure. Although Suicide Squad 3 isn't yet confirmed, there's always a chance he could show up in Aquaman 2 as an adversary, even for a brief scene or two. And it's possible both Agee and Stallone would want to return again in the future.
