Sakaarson is a prophecy stating that a hero would free the people of Sakaar. The contrast to the Sakaarson is the World Breaker, the person who would bring ruin to the planet. It was briefly thought that the Sakaarson was Red King as he saved the natives during the Spike Wars. Many, such as the Shadow Priesthood hailed him as such, but many, like Hiroim and Elloe Kaifi, felt he wasn't. Eventually the Hulk came from the planet Earth and he ended Red King's reign and was considered the Sakaarson.
In the comics it is never clearly stated just who is the true Sakaarson. Red King and later Hulk were considered as such just like the video. However, the S.H.I.E.L.D. Space Shuttle blew up destroying most of the planet, thus bringing up the possibility that Hulk was actually the World Breaker.