Worf

Worf, played by Michael Dorn, is a main character in Star Trek: The Next Generation and in seasons four to seven of Star Trek: Deep Space Nine. He also appears in the films based on The Next Generation. Worf is the first Klingon main character to appear in Star Trek, and has appeared in more Star Trek franchise episodes than any other character. Worf was the only character to be a regular in more than one live-action Star Trek series (While Miles O'Brien was featured in both The Next Generation and Deep Space Nine, he was not a regular cast member in the former series).