Mister Sinister is a supervillain appearing in American comic books published by Marvel Comics. Created by writer Chris Claremont, the character was first mentioned as the employer behind the team of assassins known as the Marauders in The Uncanny X-Men #212, and later seen in silhouette in The Uncanny X-Men #213, with both issues serving as chapters of the 1986 "Mutant Massacre" crossover. Mr. Sinister then made his first full appearance in The Uncanny X-Men #221. His appearance was designed by artist Marc Silvestri.
Sinister as depicted in Ultimate X-Men #46 (July 2004). Art by Brandon Peterson.
Christopher S. Claremont is an American comic book writer and novelist, known for his 16-year stint on Uncanny X-Men from 1975 to 1991, far longer than that of any other writer, during which he is credited with developing strong female characters as well as introducing complex literary themes into superhero narratives, turning the once underachieving comic into one of Marvel's most popular series.
Claremont at the 2016 New York Comic Con
Claremont being interviewed on breaking into the comics industry at the 2011 New York Comic Con
Claremont at the Comic New York symposium at Columbia University on March 24, 2012