Heimdall is a character for the 'Thor' comic books published by Marvel Comics. He was created by Stan Lee, Larry Lieber, and Jack Kirby and first appeared in 1962. As with Harvey Dent, Heimdall was originally created as a white character. For the 2011 'Thor' film, director Kenneth Branagh decided to rely on the actor's talent instead of skin color and picked Idris Elba to play the role which was definitely the right choice.
