Lightsnake, how blind are you?
He says it went down until ONLY ONE WAS LEFT, and then that one took an Apprentice, and so on. There were only two left!
However, because you are being so exceptionally weird and dense with understanding this, I'll post the sentence after the quote as well:
"One of the themes throughout the films is that the Sith lords, when they started out thousands of years ago, embraced the dark side. They were greedy and self-centered and they all wanted to take over, so they killed each other. Eventually, there was only one left, and that one took on an apprentice. And for thousands of years, the master would teach the apprentice, the master would die, the apprentice would then teach another apprentice, become the master, and so on. But there could never be any more than two of them, because if there were, they would try to get rid of the leader."
Feel silly now? Honestly, LS, that was one of the most breathtakingly silly things I have ever seen on the forums, and I have seen a lot of silly things.