Well Royce was the first star that helped popularize the sport. Guys like Sakuraba and Wanderlai were big stars in Japan. No one has reached the heights of Bob Sapp's popularity at his peak in Japan. As for the States - Chuck Liddell was the first true crossover mega-star for the sport of MMA.
I heard of Ken Shamrock long before I heard about anybody else in MMA. "The Most Dangerous Man in the World"
I picked Chuck. Why? Because I think a superstar is someone who is a household name. Chuck was really the first to be widely recognized in the united states. This has nothing to do with fighting ability because there are better ones on that list. On a worldwide scale I would pick either Grace, or Fedor.
I'd say he was the first big star due to the WWF crossover, he was a wrestler when wrestling was the in thing as well so he is remembered by a lot of people who don't necessarily watch WWE or MMA. Gracie is the first true massive star though from that list, I would say
When I climbed aboard, Tank was the most feared (on an "on" night) and most unpredictable. Tito and Vitor were rising stars. Taktarov, Severn, Shamrock, and Gracie were the established legends of the young sport. Couture was "the man" in the glamour division. Guys like Smith, Randleman, and Coleman were right behind him.
I voted Tito, but it was actually Shamrock. Gracie wasn't a "superstar", UFC was small time back then. Ken was the first guy to actually bring it to mainstream, Tito took it to another level. When most people hear UFC, Shamrock and Ortiz pop into their heads before Gracie most likely
Used to be big into watching WWE..when Ken Shamrock came over was the first time I heard about UFC. Sparked some interest in "real" fighting so I checked it out. Local video store had some VHS from all the events so far and I started renting them. First fighters I knew were Ken Shamrock and Royce Gracie. Also Severn but not so much. Then came the new wave of guys with the Ultimate Fighting Championship came out on Playstation. Ended up seeing Tito as the star after that. But first superstar..I'd say Shamrock because I'd never heard of Gracie outside of UFC. And as someone who had never heard of UFC before Shamrock stood out to me.