10 Star Trek Characters Who Appeared On Multiple Series
8. Kor, Koloth And Kang
This trio of Klingons as been causing problems for the Federation for years.
Kor was the first named Klingon to appear on The Original Series. Koloth and Kang followed shortly after. They faced off against Kirk separately more than one time, though they occasionally worked alongside him when the situation called for it. Just because you're a Klingon doesn't mean you can't be reasonable from time to time.
All three warriors eventually appeared together on Deep Space Nine. They were allies of Curzon Dax, a Trill member of Starfleet. Together, the four of them had sworn a blood oath to kill a marauding Albino who had murdered their first born children, one of whom was Dax's godchild. When the symbiote was transferred to Jadzia Dax, she joined them to help kill the Albino.
Koloth and Kang died in the attack. Kor returned to DS9 a couple of more times, eventually sacrificing himself during the Dominion War to save his Klingon brothers and sisters. Kang appeared one more time in Voyager in an episode that flashed back to the events of the sixth Star Trek movie. In it, Captain HIkaru Sulu's USS Excelsior faced off against a Klingon ship commanded by Kang.
It's more than worth noting that George Takei appeared in the same Voyager episode, reprising his role as Sulu from The Original Series.