What about the time, between Darht Bane and the first seen Sith?

Does anybody know something about the time between this two great Sith warriors?
Darht Bane said, there will be only two Sith. And there were only two Sith. Is he a god or something?
First the Sith fighted eachother, then they listen to Darht Bane. Does this mean, the Sith know there search for power and greatness were there weakest part?
I believe it is, because the Jedi apprentices defeated Exar Kun for the second time on Yavin 4, because they knew this was there weakness. But aren't the Sith not stronger when they know there weak parts.

And why does the Emperor disobey the order of Darht Bane? Because he Knew he had Anakin on his side?
When he really was a great Sith Lord, he could have forseen this in the Future.
Questions, questions.....
Whow know the answers?

 

Darth Bane lived a long time before Palpatine. During his time, there were a lot of Sith but I think they destroyed each other in some kind of bid for power. In the end, he was the only one left, so he made that rule so it wouldn't happen again.

 

yes, that is what I said. First a lot of Sith. Then destroyed eachother. And at last darht Bane. But the question was: Whow are the Sith between Bane and Sidious? Do we, Starwars freaks, know anything about those Sith?