Pavel Chekov is a fictional male Human in the Star Trek - The Original Series series. The character was portrayed on screen by Walter Koenig, Anton Yelchin. His allegiance / loyalty is to The USS Enterprise NCC-1701A. His character was added after a report in Pravda, the Russian newspapers which criticised the show for not having Russians in the series. His first episode was called Catspaw. He was in the B-Team of main characters rather than in the group that contained Capt. James Tiberius Kirk and Spock.
When the original series was rebooted, the role of Chekov was played by Anton Yelchin. Anton was born in Leningrad, Soviet Union as it was at the time, now known St. Petersburg, Russia, the second largest city in Russia after Moscow.
His character wasn't a major character, he was seen at the controls at the front of the bridge as in it had been in the original series. Chekov was a sprightly character. He appeared in the first three rebooted movies before disaster happened in real-life. Anton Yelchin was killed in a freak accident involving his car. Paramount announced they would not be replacing Anton and that the character would not be appearing in the future films with the same cast.