Worf

Worf is a ' and ' character. He is played by Michael Dorn. He serves on the starship Enterprise as Lieutenant Junior Grade. Worf is the first Klingon main character to appear in Star Trek, and has appeared in more Star Trek episodes than any other character.
Character story.
Worf is the son of Mogh. When Worf was a child, his parents and family were killed by the Romulan attack on the Khitomer outpost. Worf, his nanny Kahlest, and his brother Kurn survived the attack. Worf was then adopted by a human couple, Sergey and Helena Rozhenko while his brother was raised in the Klingon homeworld; this was not revealed until they were both adults. Although Worf never took the Rozhenko's last name, for he preferred to be addressed as "Worf, son of Mogh". It was during his time on gault that the 13-year-old Worf, captain of his school's soccer team accidentally killed another boy during a championship by throwing himself at him as the two children ran after the ball which flew in the air. This was something Worf would never forget.