(written from a Production point of view)
Arnold Moss (28 January 1910 – 15 December 1989; age 79), a long-time character actor, began his career on Broadway in 1930 and continued to perform plays there until the late 1950s. In the mid-1940s, he added television and movies to his acting range, working there until the late 1970s. He was the father of Jeff Moss, a founding writer of the PBS television program Sesame Street. Lung cancer took his life on 15 December 1989. 
He made one Star Trek appearance in the Star Trek: The Original Series first season episode "The Conscience of the King" as Anton Karidian/Kodos the Executioner. He filmed his scenes between Wednesday 14 September 1966 and Friday 16 September 1966, and on Wednesday 21 September 1966 at Desilu Stage 9 and Stage 10.
Moss co-starred in the 1949 film Border Incident, which starred Ricardo Montalban, and the 1950 MGM film Kim, based on the novel by Rudyard Kipling and co-starring Dean Stockwell as the titular character, along with Michael Ansara and Hamilton Camp (in uncredited roles). He also appeared in the 1965 movie The Fool Killer with Salome Jens.