Warner Bros. has revealed that Willem Dafoe will play Aquaman's mentor Nuidis Vulko in the upcoming Justice League movies. Announced during a press event on the London set, the casting adds what would appear to be a key ally for Aquaman in the Justice League movies as well as the subsequent Aquaman feature. Vulko was named by Newsarama as a likely contender for Dafoe when his mystery casting was first announced.
Nuidis Vulko was created for 1967's The Brave & the Bold #73 by Bob Haney and Howard Purcell, and has been a long-time ally to Aquaman and, in some continuities, his father. At one time or another, Vulko has been Atlantis's chief scientific advisor, regent, and even king. In the line-wide reboot of DC continuity with "New 52," Vulko was portrayed as a bit of a puppet master, orchestrating the Atlantean War between the Ocean Master and Aquaman.
Justice League is scheduled to debut in theaters November 17, 2017, with Aquaman following July 27, 2018.