Aquaman director James Wan has confirmed through his official Twitter account that actor Randall Park is playing Dr. Shin in the movie.
In the comics, Stephen Shin is a professor of theoretical marine biology and a friend to Aquaman’s father Tom Curry, who’s being played by Temuera Morrison in the movie. Shin then helps Arthur Curry/Aquaman (Jason Momoa) as a child develop his powers, but later becomes obsessed with the location of Atlantis.
Dr. Shin is first introduced in the New 52 Aquaman comics, appearing in issue #3 in 2011. The character is also seen in the DC Comics animated movie Justice League: Throne of Atlantis.
— James Wan (@creepypuppet) April 12, 2018